Super resolution and color motion artifact correction in a pulsed fluorescence imaging system

ABSTRACT

Systems, methods, and devices for super resolution and color motion artifact correction in a pulsed fluorescence imaging system are disclosed. A method includes actuating an emitter to emit a plurality of pulses of electromagnetic radiation and sensing reflected electromagnetic radiation resulting from the plurality of pulses of electromagnetic radiation with a pixel array of an image sensor to generate a plurality of exposure frames. The method includes detecting motion across two or more sequential exposure frames of the plurality of exposure frames, compensating for the detected motion, and combining the two or more sequential exposure frames to generate an image frame. The method is such that at least a portion of the plurality of pulses of electromagnetic radiation emitted by the emitter comprises one or more of electromagnetic radiation having a wavelength from about 770 nm to about 790 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/864,213, filed Jun. 20, 2019, titled “SUPERRESOLUTION AND COLOR MOTION ARTIFACT CORRECTION IN A PULSEDHYPERSPECTRAL AND FLUORESCENCE IMAGING SYSTEM,” which is incorporatedherein by reference in its entirety, including but not limited to thoseportions that specifically appear hereinafter, the incorporation byreference being made with the following exception: In the event that anyportion of the above-referenced provisional application is inconsistentwith this application, this application supersedes the above-referencedprovisional application.

TECHNICAL FIELD

This application is directed to digital imaging and is particularlydirected to fluorescence imaging in a light deficient environment.

BACKGROUND

Advances in technology have provided advances in imaging capabilitiesfor medical use. An endoscope may be used to look inside a body andexamine the interior of an organ or cavity of the body. Endoscopes areused for investigating a patient's symptoms, confirming a diagnosis, orproviding medical treatment. A medical endoscope may be used for viewinga variety of body systems and parts such as the gastrointestinal tract,the respiratory tract, the urinary tract, the abdominal cavity, and soforth. Endoscopes may further be used for surgical procedures such asplastic surgery procedures, procedures performed on joints or bones,procedures performed on the neurological system, procedures performedwithin the abdominal cavity, and so forth.

In some instances of endoscopic imaging, it may be beneficial ornecessary to view a space in color. A digital color image includes atleast three layers, or “color channels,” that cumulatively form an imagewith a range of hues. Each of the color channels measures the intensityand chrominance of light for a spectral band. Commonly, a digital colorimage includes a color channel for red, green, and blue spectral bandsof light (this may be referred to as a Red Green Blue or RGB image).Each of the red, green, and blue color channels include brightnessinformation for the red, green, or blue spectral band of light. Thebrightness information for the separate red, green, and blue layers arecombined to create the color image. Because a color image is made up ofseparate layers, a conventional digital camera image sensor includes acolor filter array that permits red, green, and blue visible lightwavelengths to hit selected pixel sensors. Each individual pixel sensorelement is made sensitive to red, green, or blue wavelengths and willonly return image data for that wavelength. The image data from thetotal array of pixel sensors is combined to generate the RGB image. Theat least three distinct types of pixel sensors consume significantphysical space such that the complete pixel array cannot fit in thesmall distal end of an endoscope.

Because a traditional image sensor cannot fit in the distal end of anendoscope, the image sensor is traditionally located in a handpiece unitof an endoscope that is held by an endoscope operator and is not placedwithin the body cavity. In such an endoscope, light is transmitted alongthe length of the endoscope from the handpiece unit to the distal end ofthe endoscope. This configuration has significant limitations.Endoscopes with this configuration are delicate and can be easilymisaligned or damaged when bumped or impacted during regular use. Thiscan significantly degrade the quality of the images and necessitate thatthe endoscope be frequently repaired or replaced.

The traditional endoscope with the image sensor placed in the handpieceunit is further limited to capturing only color images. However, in someimplementations, it may be desirable to capture images with fluorescenceimage data in addition to color image data. Fluorescence is the emissionof light by a substance that has absorbed light or other electromagneticradiation. Certain fluorescent materials “glow” or emit a distinct colorthat is visible to the human eye when the fluorescent material issubjected to ultraviolet light or other wavelengths of electromagneticradiation. Certain fluorescent materials will cease to glow nearlyimmediately when the radiation source stops.

Fluorescence occurs when an orbital electron of a molecule, atom, ornanostructure is excited by light or other electromagnetic radiation,and then relaxes to its ground state by emitting a photon from theexcited state. The specific frequencies of electromagnetic radiationthat excite the orbital electron, or are emitted by the photon duringrelaxation, are dependent on the atom, molecule, or nanostructure.Fluorescence imaging has numerous practical applications, includingmineralogy, gemology, medicine, spectroscopy for chemical sensors,detecting biological processes or signals, and others. Fluorescence canbe used in biochemistry and medicine as a non-destructive means fortracking or analyzing biological molecules. Some fluorescent reagents ordyes can be configured to attach to certain types of tissue and therebydraw attention to that type of tissue.

However, fluorescence imaging requires specialized emissions ofelectromagnetic radiation and specialized imaging sensors capable ofreading the specific relaxation wavelength for a specific fluorescentreagent. Different reagents or dyes are sensitive to differentwavelengths of electromagnetic radiation and emit different wavelengthsof electromagnetic radiation when fluoresced. A fluorescent imagingsystem may be highly specialized and tuned for a certain reagent or dye.Such imaging systems are useful for limited applications and are notcapable of fluorescing more than one reagent or structure during asingle imaging session. It is very costly to use multiple distinctimaging systems that are each configured for fluorescing a differentreagent. Additionally, it may be desirable to administer multiplefluorescent reagents in a single imaging session and view the multiplereagents in a single overlaid image.

In light of the foregoing, described herein are systems, methods, anddevices for fluorescent imaging in a light deficient environment. Suchsystems, methods, and devices may provide multiple datasets foridentifying critical structures in a body and providing precise andvaluable information about the body cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive implementations of the disclosure aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified. Advantages of the disclosure will becomebetter understood with regard to the following description andaccompanying drawings where:

FIG. 1 is a schematic view of a system for digital imaging in a lightdeficient environment with a paired emitter and pixel array;

FIG. 2 is a system for providing illumination to a light deficientenvironment for endoscopic imaging;

FIG. 2A is a schematic diagram of complementary system hardware;

FIGS. 3A to 3D are illustrations of the operational cycles of an imagesensor used to construct one or more exposure frames;

FIG. 4A is a graphical representation of the operation of an embodimentof an electromagnetic emitter;

FIG. 4B is a graphical representation of varying the duration andmagnitude of the emitted electromagnetic pulse to provide exposurecontrol;

FIG. 5 is a graphical representation of an embodiment of the disclosurecombining the operational cycles of an image sensor, an electromagneticemitter, and the emitted electromagnetic pulses of FIGS. 3A-4A, whichdemonstrate the imaging system during operation;

FIG. 6A is a schematic diagram of a process for recording a video withfull spectrum light over a period of time from t(0) to t(1);

FIG. 6B is a schematic diagram of a process for recording a video bypulsing portioned spectrum light over a period of time from t(0) tot(1);

FIGS. 7A-7E illustrate schematic views of processes over an interval oftime for recording a frame of video for both full spectrum light andpartitioned spectrum light;

FIG. 8 is a schematic diagram of a process flow to be implemented by acontroller or image signal processor for generating a video stream withRGB image frames and fluorescence data overlaid on the RGB image frame;

FIG. 9 is a schematic diagram of a process flow for applying superresolution and color motion artifact correction processes to image datathat may include luminance, chrominance, and fluorescence data forgenerating a YCbCr or RGB image with fluorescence data overlaid thereon;

FIG. 10 is a schematic of an example pixel array configured in an x andy plane that may be used to implement the process flow illustrated inFIG. 9 for applying the super resolution and color motion artifactcorrection processes to image data;

FIG. 11 is a schematic of an example pixel array wherein luminancepixels are shifted in the x and y directions for comparing pixel data toan equivalent block in that location in a different exposure frame infurtherance of applying super resolution and color motion artifactprocesses to image data;

FIG. 12 illustrates an example scene wherein a ball is traveling throughthe scene at a quicker rater than the rate of capture for multipleexposure frames sensed by a pixel array of an image sensor;

FIG. 13 is a schematic diagram of a pattern reconstruction process forgenerating an RGB image frame with fluorescence image data overlaidthereon;

FIGS. 14A-14C illustrate a light source having a plurality of emitters;

FIG. 15 illustrates a single optical fiber outputting via a diffuser atan output to illuminate a scene in a light deficient environment;

FIG. 16 illustrates a portion of the electromagnetic spectrum dividedinto a plurality of different sub-spectrums which may be emitted byemitters of a light source in accordance with the principles andteachings of the disclosure;

FIG. 17 is a schematic diagram illustrating a timing sequence foremission and readout for generating an image frame comprising aplurality of exposure frames resulting from differing partitions ofpulsed light;

FIG. 18 illustrates an imaging system including a single cut filter forfiltering wavelengths of electromagnetic radiation;

FIG. 19 illustrates an imaging system comprising a multiple cut filterfor filtering wavelengths of electromagnetic radiation;

FIGS. 20A and 20B illustrate an implementation having a plurality ofpixel arrays for producing a three-dimensional image in accordance withthe principles and teachings of the disclosure;

FIGS. 21A and 21B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor built on aplurality of substrates, wherein a plurality of pixel columns formingthe pixel array are located on the first substrate and a plurality ofcircuit columns are located on a second substrate and showing anelectrical connection and communication between one column of pixels toits associated or corresponding column of circuitry; and

FIGS. 22A and 22B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor having aplurality of pixel arrays for producing a three-dimensional image,wherein the plurality of pixel arrays and the image sensor are built ona plurality of substrates.

DETAILED DESCRIPTION

Disclosed herein are systems, methods, and devices for digital imagingthat may be primarily suited to medical applications such as medicalendoscopic imaging. An embodiment of the disclosure is an endoscopicsystem for fluorescence and/or color imaging in a light deficientenvironment.

Conventional endoscopes are designed such that the image sensor isplaced at a proximal end of the device within a handpiece unit. Thisconfiguration requires that incident light travel the length of theendoscope by way of precisely coupled optical elements. The preciseoptical elements can easily be misaligned during regular use, and thiscan lead to image distortion or image loss. Embodiments of thedisclosure place an image sensor within a distal end of the endoscopeitself. This provides greater optical simplicity when compared withimplementations known in the art. However, an acceptable solution tothis approach is by no means trivial and introduces its own set ofengineering challenges, not least of which that the image sensor mustfit within a highly constrained area.

The imaging systems disclosed herein place aggressive constraints on thesize of the image sensor. This enables the image sensor to be placed ina distal end of an endoscope and thereby enables the correspondingbenefits of improved optical simplicity and increased mechanicalrobustness for the endoscope. However, placing these aggressiveconstraints on the image sensor area results in fewer and/or smallerpixels and can degrade image quality. An embodiment of the disclosureovercomes this challenge by incorporating a monochrome image sensor withminimal peripheral circuitry, connection pads, and logic. The imagingsystems disclosed herein provide means for extending the dynamic range,sensor sensitivity, and spatial resolution of resultant images whilestill decreasing the overall size of the image sensor through theapplication of super resolution and color motion artifact correctionalgorithms.

In an embodiment, the super resolution algorithm is deployed to enhanceperceived resolution of an image and extract motion information from aseries of sequential exposure frames that are captured sequentially intime. Each of the sequential exposure frames is generated by a pixelarray of an image sensor. The pixel array senses reflectedelectromagnetic radiation from a pulse of electromagnetic radiation thatis emitted by an emitter. The pulses of electromagnetic radiation mayinclude red, green, blue, and/or fluorescence pulses for generating redexposure frames, green exposure frames, blue exposure frames, and/orfluorescence exposure frames. A grouping of sequential exposure framesare combined to generate an image frame with increased spatialresolution when compared with the individual exposure frames. The superresolution algorithm and the color motion artifact correction processesdisclosed herein detect motion in a scene, correct for the detectedmotion, and increase spatial resolution of a resultant image frame bycombining multiple exposure frames.

For digital imaging systems, the final quality of a video stream dependson engineering details of the electronic capture process deployed by theimage sensor. The perceived quality of an image frame is dependent on,among other things, the signal to noise ratio (SNR), the dynamic range(DR), the spatial resolution, the perception of visible unnaturalartifacts, the perception of spatial distortion, and the color fidelityand appeal of the image frame. Each of these factors can be negativelyimpacted by decreasing the overall size of the image sensor. Therefore,in an effort to increase the perceived quality of a resultant imageframe, traditional cameras known in the art include multiple imagesensors or include an enlarged image sensor. For example, high-endcameras that can produce high resolution images typically include atleast three monochrome sensors that are precisely coupled in anelaborate arrangement of prisms and filters. Another traditionalsolution is to use a single sensor with individual pixel-sized colorfilters fabricated on to the image sensor in a mosaic arrangement. Themost popular mosaic arrangement is the Bayer pattern. An image sensorwith a Bayer pattern can be inexpensive to fabricate but cannot achievethe image quality realized by the three-image sensor solutionimplemented in high-end cameras. An additional undesirable side effectof the Bayer pattern is that the color segmentation pattern introducesartifacts in the resultant image frames, and these artifacts can beespecially noticeable around black and white edges.

One traditional approach to decreasing the size of the image sensor isto increase the number of pixels in the pixel array and reduce the sizeof the individual pixels. However, smaller pixels naturally have lowersignal capacity. The lower signal capacity reduces the dynamic range ofdata captured by the pixels and reduces the maximum possible signal tonoise ratio. Decreasing the area of an individual pixel reduces thesensitivity of the pixel not only in proportion with the capture area ofthe pixel but to a greater degree. The loss of sensitivity for the pixelmay be compensated by widening the aperture, but this leads to ashallower depth of field and shallower depth of focus. The shallowerdepth of field impacts the resolution of the resultant image and canlead to greater spatial distortion. Additionally, smaller pixels aremore challenging to manufacture consistently, and this may result ingreater defect rates.

In light of the deficiencies associated with decreasing the capture areaof the pixels, disclosed herein are systems, methods, and devices forreducing pixel count and bolstering image resolution by other means. Inan embodiment, a monochrome image sensor is used with “color agnostic”pixels in the pixel array. The color information is determined bycapturing independent exposure frames in response to pulses of differentwavelengths of electromagnetic radiation. The alternative pulses mayinclude red, green, and blue wavelengths for generating an RGB imageframe consisting of a red exposure frame, a green exposure frame, and ablue exposure frame. The image frame may further include data from afluorescence exposure frame overlaid on the RGB image frame. Thefluorescence pulse may include one or more pulses of electromagneticradiation for exciting a fluorescent reagent. In an embodiment, thefluorescence excitation emission includes one or more of electromagneticradiation having a wavelength from about 795 nm to about 815 nm.

In an embodiment, each pulse or grouping of pulses of electromagneticradiation results in an exposure frame sensed by the pixel array. Aplurality of exposure frames may be combined to generate an image frame.The image frame may include, for example, a red exposure frame generatedin response to a red pulse, a green exposure frame generated in responseto a green pulse, a blue exposure frame generated in response to a bluepulse, and a fluorescence exposure frame generated in response to afluorescence pulse. The red, green, blue, and fluorescence exposureframes can be combined to generate a single RGB image frame withfluorescence data overlaid thereon. This method results in increaseddynamic range and spatial resolution in the resultant image frame.However, this method can introduce motion blur because the multipleexposure frames making up the image frame are captured over time.Additionally, because the independent exposure frames supply differentcolor components, the image frame can have unnatural colored effectsthat may be particularly visible in the vicinity of large edges. Inlight of the foregoing, the systems, methods, and devices disclosedherein correct for motion introduced by frame-wise color switching.

In some instances, it is desirable to generate endoscopic imaging withmultiple data types or multiple images overlaid on one another. Forexample, it may be desirable to generate an RGB image frame that furtherincludes fluorescence imaging data overlaid on the RGB image frame. Anoverlaid image of this nature may enable a medical practitioner orcomputer program to identify critical body structures based on thefluorescence imaging data. Historically, this would require the use ofmultiple sensor systems including an image sensor for color imaging andone or more additional image sensors for fluorescence imaging. In suchsystems, the multiple image sensors would have multiple types of pixelsensors that are each sensitive to distinct ranges of electromagneticradiation. In systems known in the art, this includes the three separatetypes of pixel sensors for generating an RGB color image along withadditional pixel sensors for generating the fluorescence image data atdifferent wavelengths of the electromagnetic spectrum. Traditionally,these multiple different pixel arrays consume a prohibitively largephysical space and cannot be located at a distal tip of the endoscope.Considering the foregoing, disclosed herein are systems, methods, anddevices for endoscopic imaging in a light deficient environment. Thesystems, methods, and devices disclosed herein provide means foremploying multiple imaging techniques in a single imaging session whilepermitting one or more image sensors to be disposed in a distal tip ofthe endoscope.

Fluorescence Imaging

The systems, methods, and devices disclosed herein provide means forgenerating fluorescence imaging data in a light deficient environment.The fluorescence imaging data may be used to identify certain materials,tissues, components, or processes within a body cavity or other lightdeficient environment. In certain embodiments, fluorescence imaging isprovided to a medical practitioner or computer-implemented program toenable the identification of certain structures or tissues within abody. Such fluorescence imaging data may be overlaid on black-and-whiteor RGB images to provide additional information and context.

Fluorescence is the emission of light by a substance that has absorbedlight or other electromagnetic radiation. Certain fluorescent materialsmay “glow” or emit a distinct color that is visible to the human eyewhen the fluorescent material is subjected to ultraviolet light or otherwavelengths of electromagnetic radiation. Certain fluorescent materialswill cease to glow nearly immediately when the radiation source stops.

Fluorescence occurs when an orbital electron of a molecule, atom, ornanostructure is excited by light or other electromagnetic radiation,and then relaxes to its ground state by emitting a photon from theexcited state. The specific frequencies of electromagnetic radiationthat excite the orbital electron, or are emitted by the photon duringrelaxation, are dependent on the particular atom, molecule, ornanostructure. In most cases, the light emitted by the substance has alonger wavelength, and therefore lower energy, than the radiation thatwas absorbed by the substance. However, when the absorbedelectromagnetic radiation is intense, it is possible for one electron toabsorb two photons. This two-photon absorption can lead to emission ofradiation having a shorter wavelength, and therefore higher energy, thanthe absorbed radiation. Additionally, the emitted radiation may also bethe same wavelength as the absorbed radiation.

Fluorescence imaging has numerous practical applications, includingmineralogy, gemology, medicine, spectroscopy for chemical sensors,detecting biological processes or signals, and so forth. Fluorescencemay particularly be used in biochemistry and medicine as anon-destructive means for tracking or analyzing biological molecules.The biological molecules, including certain tissues or structures, maybe tracked by analyzing the fluorescent emission of the biologicalmolecules after being excited by a certain wavelength of electromagneticradiation. However, relatively few cellular components are naturallyfluorescent. In certain implementations, it may be desirable tovisualize a certain tissue, structure, chemical process, or biologicalprocess that is not intrinsically fluorescent. In such animplementation, the body may be administered a dye or reagent that mayinclude a molecule, protein, or quantum dot having fluorescentproperties. The reagent or dye may then fluoresce after being excited bya certain wavelength of electromagnetic radiation. Different reagents ordyes may include different molecules, proteins, and/or quantum dots thatwill fluoresce at particular wavelengths of electromagnetic radiation.Thus, it may be necessary to excite the reagent or dye with aspecialized band of electromagnetic radiation to achieve fluorescenceand identify the desired tissue, structure, or process in the body.

Fluorescence imaging may provide valuable information in the medicalfield that may be used for diagnostic purposes and/or may be visualizedin real-time during a medical procedure. Specialized reagents or dyesmay be administered to a body to fluoresce certain tissues, structures,chemical processes, or biological processes. The fluorescence of thereagent or dye may highlight body structures such as blood vessels,nerves, particular organs, and so forth. Additionally, the fluorescenceof the reagent or dye may highlight conditions or diseases such ascancerous cells or cells experiencing a certain biological or chemicalprocess that may be associated with a condition or disease. Thefluorescence imaging may be used in real-time by a medical practitioneror computer program for differentiating between, for example, cancerousand non-cancerous cells during a surgical tumor extraction. Thefluorescence imaging may further be used as a non-destructive means fortracking and visualizing over time a condition in the body that wouldotherwise not be visible by the human eye or distinguishable in an RGBimage.

The systems, methods, and devices for generating fluorescence imagingdata may be used in coordination with reagents or dyes. Some reagents ordyes are known to attach to certain types of tissues and fluoresce atspecific wavelengths of the electromagnetic spectrum. In animplementation, a reagent or dye is administered to a patient that isconfigured to fluoresce when activated by certain wavelengths of light.The endoscopic imaging system disclosed herein is used to excite andfluoresce the reagent or dye. The fluorescence of the reagent or dye iscaptured by the endoscopic imaging system to aid in the identificationof tissues or structures in the body cavity. In an implementation, apatient is administered a plurality of reagents or dyes that are eachconfigured to fluoresce at different wavelengths and/or provide anindication of different structures, tissues, chemical reactions,biological processes, and so forth. In such an implementation, theendoscopic imaging system emits each of the applicable wavelengths tofluoresce each of the applicable reagents or dyes. This may negate theneed to perform individual imaging procedures for each of the pluralityof reagents or dyes.

Imaging reagents can enhance imaging capabilities in pharmaceutical,medical, biotechnology, diagnostic, and medical procedure industries.Many imaging techniques such as X-ray, computer tomography (CT),ultrasound, magnetic resonance imaging (MRI), and nuclear medicine,mainly analyze anatomy and morphology and are unable to detect changesat the molecular level. Fluorescent reagents, dyes, and probes,including quantum dot nanoparticles and fluorescent proteins, assistmedical imaging technologies by providing additional information aboutcertain tissues, structures, chemical processes, and/or biologicalprocesses that are present within the imaging region. Imaging usingfluorescent reagents enables cell tracking and/or the tracking ofcertain molecular biomarkers. Fluorescent reagents may be applied forimaging cancer, infection, inflammation, stem cell biology, and others.Numerous fluorescent reagents and dyes are being developed and appliedfor visualizing and tracking biological processes in a non-destructivemanner. Such fluorescent reagents may be excited by a certain wavelengthor band of wavelengths of electromagnetic radiation. Similarly, thosefluorescent reagents may emit relaxation energy at a certain wavelengthor band of wavelengths when fluorescing, and the emitted relaxationenergy may be read by a sensor to determine the location and/orboundaries of the reagent or dye.

In an embodiment of the disclosure, an endoscopic imaging system pulseselectromagnetic radiation for exciting an electron in a fluorescentreagent or dye. The endoscopic imaging system may pulse multipledifferent wavelengths of electromagnetic radiation for fluorescingmultiple different reagents or dyes during a single imaging session. Theendoscope includes an image sensor that is sensitive to the relaxationwavelength(s) of the one or more reagents or dyes. The imaging datagenerated by the image sensor can be used to identify a location andboundary of the one or more reagents or dyes. The endoscope system mayfurther pulse electromagnetic radiation in red, green, and blue bands ofvisible light such that the fluorescence imaging can be overlaid on anRGB video stream.

Pulsed Imaging

Some implementations of the disclosure include aspects of a combinedsensor and system design that allows for high definition imaging withreduced pixel counts in a controlled illumination environment. This isaccomplished with frame-by-frame pulsing of a single-color wavelengthand switching or alternating each frame between a single, differentcolor wavelength using a controlled light source in conjunction withhigh frame capture rates and a specially designed correspondingmonochromatic sensor. Additionally, electromagnetic radiation outsidethe visible light spectrum may be pulsed to enable the generation of afluorescence image. The pixels may be color agnostic such that eachpixel generates data for each pulse of electromagnetic radiation,including pulses for red, green, and blue visible light wavelengthsalong with other wavelengths used for fluorescence imaging.

For the purposes of promoting an understanding of the principles inaccordance with the disclosure, reference will now be made to theembodiments illustrated in the drawings and specific language will beused to describe the same. It will nevertheless be understood that nolimitation of the scope of the disclosure is thereby intended. Anyalterations and further modifications of the inventive featuresillustrated herein, and any additional applications of the principles ofthe disclosure as illustrated herein, which would normally occur to oneskilled in the relevant art and having possession of this disclosure,are to be considered within the scope of the disclosure claimed.

Before the structure, systems and methods for producing an image in alight deficient environment are disclosed and described, it is to beunderstood that this disclosure is not limited to the particularstructures, configurations, process steps, and materials disclosedherein as such structures, configurations, process steps, and materialsmay vary somewhat. It is also to be understood that the terminologyemployed herein is used for the purpose of describing particularembodiments only and is not intended to be limiting since the scope ofthe disclosure will be limited only by the appended claims andequivalents thereof.

In describing and claiming the subject matter of the disclosure, thefollowing terminology will be used in accordance with the definitionsset out below.

It must be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the context clearly dictates otherwise.

As used herein, the terms “comprising,” “including,” “containing,”“characterized by,” and grammatical equivalents thereof are inclusive oropen-ended terms that do not exclude additional, unrecited elements ormethod steps.

As used herein, the phrase “consisting of” and grammatical equivalentsthereof exclude any element or step not specified in the claim.

As used herein, the phrase “consisting essentially of” and grammaticalequivalents thereof limit the scope of a claim to the specifiedmaterials or steps and those that do not materially affect the basic andnovel characteristic or characteristics of the claimed disclosure.

As used herein, the term “proximal” shall refer broadly to the conceptof a portion nearest an origin.

As used herein, the term “distal” shall generally refer to the oppositeof proximal, and thus to the concept of a portion farther from anorigin, or a furthest portion, depending upon the context.

As used herein, color sensors or multi spectrum sensors are thosesensors known to have a color filter array (CFA) thereon to filter theincoming electromagnetic radiation into its separate components. In thevisual range of the electromagnetic spectrum, such a CFA may be built ona Bayer pattern or modification thereon to separate green, red and bluespectrum components of the light.

As used herein, monochromatic sensor refers to an unfiltered imagingsensor. Because the pixels are color agnostic, the effective spatialresolution is appreciably higher than for color (typically Bayer-patternfiltered) counterparts in conventional single-sensor cameras.Monochromatic sensors may also have higher quantum efficiency becausefewer incident photons are wasted between individual pixels.

As used herein, an emitter is a device that is capable of generating andemitting electromagnetic pulses. Various embodiments of emitters may beconfigured to emit pulses and have very specific frequencies or rangesof frequencies from within the entire electromagnetic spectrum. Pulsesmay comprise wavelengths from the visible and non-visible ranges. Anemitter may be cycled on and off to produce a pulse or may produce apulse with a shutter mechanism. An emitter may have variable poweroutput levels or may be controlled with a secondary device such as anaperture or filter. An emitter may emit broad spectrum or full spectrumelectromagnetic radiation that may produce pulses through colorfiltering or shuttering. An emitter may comprise a plurality ofelectromagnetic sources that act individually or in concert.

It should be noted that as used herein the term “light” is both aparticle and a wavelength and is intended to denote electromagneticradiation that is detectable by a pixel array and may includewavelengths from the visible and non-visible spectrums ofelectromagnetic radiation. The term “partition” is used herein to mean apre-determined range of wavelengths of the electromagnetic spectrum thatis less than the entire spectrum, or in other words, wavelengths thatmake up some portion of the electromagnetic spectrum. As used herein, anemitter is a light source that may be controllable as to the portion ofthe electromagnetic spectrum that is emitted or that may operate as tothe physics of its components, the intensity of the emissions, or theduration of the emission, or all the above. An emitter may emit light inany dithered, diffused, or collimated emission and may be controlleddigitally or through analog methods or systems. As used herein, anelectromagnetic emitter is a source of a burst of electromagnetic energyand includes light sources, such as lasers, LEDs, incandescent light, orany light source that can be digitally controlled.

Referring now to the figures, FIG. 1 illustrates a schematic diagram ofa system 100 for sequential pulsed imaging in a light deficientenvironment. The system 100 can be deployed to generate an RGB imagewith fluorescence imaging data overlaid on the RGB image. The system 100includes an emitter 102 and a pixel array 122. The emitter 102 pulses apartition of electromagnetic radiation in the light deficientenvironment 112 and the pixel array 122 senses instances of reflectedelectromagnetic radiation. The emitter 102 and the pixel array 122 workin sequence such that one or more pulses of a partition ofelectromagnetic radiation results in image data sensed by the pixelarray 122.

It should be noted that as used herein the term “light” is both aparticle and a wavelength and is intended to denote electromagneticradiation that is detectable by a pixel array 122 and may includewavelengths from the visible and non-visible spectrums ofelectromagnetic radiation. The term “partition” is used herein to mean apre-determined range of wavelengths of the electromagnetic spectrum thatis less than the entire spectrum, or in other words, wavelengths thatmake up some portion of the electromagnetic spectrum. As used herein, anemitter is a light source that may be controllable as to the portion ofthe electromagnetic spectrum that is emitted or that may operate as tothe physics of its components, the intensity of the emissions, or theduration of the emission, or all the above. An emitter may emit light inany dithered, diffused, or collimated emission and may be controlleddigitally or through analog methods or systems. As used herein, anelectromagnetic emitter is a source of a burst of electromagnetic energyand includes light sources, such as lasers, LEDs, incandescent light, orany light source that can be digitally controlled.

A pixel array 122 of an image sensor may be paired with the emitter 102electronically, such that the emitter 102 and the pixel array 122 aresynced during operation for both receiving the emissions and for theadjustments made within the system. The emitter 102 may be tuned to emitelectromagnetic radiation in the form of a laser, which may be pulsed toilluminate a light deficient environment 112. The emitter 102 may pulseat an interval that corresponds to the operation and functionality ofthe pixel array 122. The emitter 102 may pulse light in a plurality ofelectromagnetic partitions such that the pixel array receiveselectromagnetic energy and produces a dataset that corresponds in timewith each specific electromagnetic partition. For example, FIG. 1illustrates an implementation wherein the emitter 102 emits fourdifferent partitions of electromagnetic radiation, including red 104,green 106, blue 108, and a fluorescence excitation 110 wavelength. Thefluorescence excitation 110 wavelength may include a plurality ofdifferent partitions of electromagnetic radiation that are selected tofluoresce a plurality of fluorescent reagents that are present withinthe light deficient environment 112. The fluorescent excitation 110wavelength may be selected to fluoresce a particular fluorescent reagentthat is present in the light deficient environment 112.

The light deficient environment 112 includes structures, tissues, andother elements that reflect a combination of red 114, green 116, and/orblue 118 light. A structure that is perceived as being red 114 willreflect back pulsed red 104 light. The reflection off the red structureresults in sensed red 105 by the pixel array 122 following the pulsedred 104 emission. The data sensed by the pixel array 122 results in ared exposure frame. A structure that is perceived as being green 116will reflect back pulsed green 106 light. The reflection off the greenstructure results in sensed green 107 by the pixel array 122 followingthe pulsed green 106 emission. The data sensed by the pixel array 122results in a green exposure frame. A structure that is perceived asbeing blue 118 will reflect back pulsed blue 108 light. The reflectionoff the blue structure results in sensed blue 109 by the pixel array 122following the pulsed blue 108 emission. The data sensed by the pixelarray 122 results in a blue exposure frame.

When a structure is a combination of colors, the structure will reflectback a combination of the pulsed red 104, pulsed green 106, and/orpulsed blue 108 emissions. For example, a structure that is perceived asbeing purple will reflect back light from the pulsed red 104 and pulsedblue 108 emissions. The resulting data sensed by the pixel array 122will indicate that light was reflected in the same region following thepulsed red 104 and pulsed blue 108 emissions. When the resultant redexposure frame and blue exposure frames are combined to form the RGBimage frame, the RGB image frame will indicate that the structure ispurple.

In an embodiment where the light deficient environment 112 includes afluorescent reagent or dye or includes one or more fluorescentstructures, tissues, or other elements, the pulsing scheme may includethe emission of a certain fluorescence excitation wavelength. Thecertain fluorescence excitation wavelength may be selected to fluorescea known fluorescent reagent, dye, or other structure. The fluorescentstructure will be sensitive to the fluorescence excitation wavelengthand will emit a fluorescence relaxation wavelength. The fluorescencerelaxation wavelength will be sensed by the pixel array 122 followingthe emission of the fluorescence excitation wavelength. The data sensedby the pixel array 122 results in a fluorescence exposure frame. Thefluorescence exposure frame may be combined with multiple other exposureframes to form an image frame. The data in the fluorescence exposureframe may be overlaid on an RGB image frame that includes data from ared exposure frame, a green exposure frame, and a blue exposure frame.

In an embodiment where the light deficient environment 112 includesstructures, tissues, or other materials that emit a spectral response tocertain partitions of the electromagnetic spectrum, the pulsing schememay include the emission of a hyperspectral partition of electromagneticradiation for the purpose of eliciting the spectral response from thestructures, tissues, or other materials present in the light deficientenvironment 112. The spectral response includes the emission orreflection of certain wavelengths of electromagnetic radiation. Thespectral response can be sensed by the pixel array 122 and result in ahyperspectral exposure frame. The hyperspectral exposure frame may becombined with multiple other exposure frames to form an image frame. Thedata in the hyperspectral exposure frame may be overlaid on an RGB imageframe that includes data from a red exposure frame, a green exposureframe, and a blue exposure frame.

In an embodiment, the pulsing scheme includes the emission of a lasermapping or tool tracking pattern. The reflected electromagneticradiation sensed by the pixel array 122 following the emission of thelaser mapping or tool tracking pattern results in a laser mappingexposure frame. The data in the laser mapping exposure frame may beprovided to a corresponding system to identify, for example, distancesbetween tools present in the light deficient environment 112, athree-dimensional surface topology of a scene in the light deficientenvironment 112, distances, dimensions, or positions of structures orobjects within the scene, and so forth. This data may be overlaid on anRGB image frame or otherwise provided to a user of the system.

The emitter 102 may be a laser emitter that is capable of emittingpulsed red 104 light for generating sensed red 105 data for identifyingred 114 elements within the light deficient environment 112. The emitter102 is further capable of emitting pulsed green 106 light for generatingsensed green 107 data for identifying green 116 elements within thelight deficient environment. The emitter 102 is further capable ofemitting pulsed blue 108 light for generating sensed blue 109 data foridentifying blue 118 elements within the light deficient environment.The emitter 102 is further capable of emitting pulsed fluorescenceexcitation 110 wavelength(s) of electromagnetic radiation foridentifying a fluorescent reagent 120 within the light deficientenvironment 112. The fluorescent reagent 120 is identified by excitingthe fluorescent reagent 120 with the pulsed fluorescence excitation 110light and then sensing (by the pixel array 122) the fluorescencerelaxation 111 wavelength for that particular fluorescent reagent 120.The emitter 102 is capable of emitting the pulsed red 104, pulsed green106, pulsed blue 108, and pulsed fluorescence excitation 110 wavelengthsin any desired sequence.

The pixel array 122 senses reflected electromagnetic radiation. Each ofthe sensed red 105, the sensed green 107, the sensed blue 109, and thesensed fluorescence relaxation 111 data can be referred to as an“exposure frame.” Each exposure frame is assigned a specific color orwavelength partition, wherein the assignment is based on the timing ofthe pulsed color or wavelength partition from the emitter 102. Theexposure frame in combination with the assigned specific color orwavelength partition may be referred to as a dataset. Even though thepixels 122 are not color-dedicated, they can be assigned a color for anygiven dataset based on a priori information about the emitter.

For example, during operation, after pulsed red 104 light is pulsed inthe light deficient environment 112, the pixel array 122 sensesreflected electromagnetic radiation. The reflected electromagneticradiation results in an exposure frame, and the exposure frame iscatalogued as sensed red 105 data because it corresponds in time withthe pulsed red 104 light. The exposure frame in combination with anindication that it corresponds in time with the pulsed red 104 light isthe “dataset.” This is repeated for each partition of electromagneticradiation emitted by the emitter 102. The data created by the pixelarray 122 includes the sensed red 105 exposure frame identifying red 114components in the light deficient environment and corresponding in timewith the pulsed red 104 light. The data further includes the sensedgreen 107 exposure frame identifying green 116 components in the lightdeficient environment and corresponding in time with the pulsed green106 light. The data further includes the sensed blue 109 exposure frameidentifying blue 118 components in the light deficient environment andcorresponding in time with the pulsed blue 108 light. The data furtherincludes the sensed fluorescence relaxation 111 exposure frameidentifying the fluorescent reagent 120 and corresponding in time withthe pulsed fluorescence excitation 110 wavelength(s) of light.

In one embodiment, three datasets representing RED, GREEN and BLUEelectromagnetic pulses are combined to form a single image frame. Thus,the information in a red exposure frame, a green exposure frame, and ablue exposure frame are combined to form a single RGB image frame. Oneor more additional datasets representing other wavelength partitions maybe overlaid on the single RGB image frame. The one or more additionaldatasets may represent, for example, fluorescence imaging responsive tothe pulsed excitation 110 wavelength between 795 nm and 815 nm.

It will be appreciated that the disclosure is not limited to anyparticular color combination or any particular electromagneticpartition, and that any color combination or any electromagneticpartition may be used in place of RED, GREEN and BLUE, such as Cyan,Magenta and Yellow; Ultraviolet; infrared; any combination of theforegoing, or any other color combination, including all visible andnon-visible wavelengths, without departing from the scope of thedisclosure. In the figure, the light deficient environment 112 to beimaged includes red 114, green 116, and blue 118 portions, and furtherincludes a fluorescent reagent 120. As illustrated in the figure, thereflected light from the electromagnetic pulses only contains the datafor the portion of the object having the specific color that correspondsto the pulsed color partition. Those separate color (or color interval)datasets can then be used to reconstruct the image by combining thedatasets at 126. The information in each of the multiple exposure frames(i.e., the multiple datasets) may be combined by a controller 124, acontrol unit, a camera control unit, the image sensor, an image signalprocessing pipeline, or some other computing resource that isconfigurable to process the multiple exposure frames and combine thedatasets at 126. The datasets may be combined to generate the singleimage frame within the endoscope unit itself or offsite by some otherprocessing resource.

FIG. 2 is a system 200 for providing illumination to a light deficientenvironment, such as for endoscopic imaging. The system 200 may be usedin combination with any of the systems, methods, or devices disclosedherein. The system 200 includes an emitter 202, a controller 204, ajumper waveguide 206, a waveguide connector 208, a lumen waveguide 210,a lumen 212, and an image sensor 214 with accompanying opticalcomponents (such as a lens). The emitter 202 (may be genericallyreferred to as a “light source”) generates light that travels throughthe jumper waveguide 206 and the lumen waveguide 210 to illuminate ascene at a distal end of the lumen 212. The emitter 202 may be used toemit any wavelength of electromagnetic energy including visiblewavelengths, infrared, ultraviolet, hyperspectral, fluorescenceexcitation, laser scanning pulsing schemes, or other wavelengths. Thelumen 212 may be inserted into a patient's body for imaging, such asduring a procedure or examination. The light is output as illustrated bydashed lines 216. A scene illuminated by the light may be captured usingthe image sensor 214 and displayed for a doctor or some other medicalpersonnel. The controller 204 may provide control signals to the emitter202 to control when illumination is provided to a scene. In oneembodiment, the emitter 202 and controller 204 are located within acamera control unit (CCU) or external console to which an endoscope isconnected. If the image sensor 214 includes a CMOS sensor, light may beperiodically provided to the scene in a series of illumination pulsesbetween readout periods of the image sensor 214 during what is known asa blanking period. Thus, the light may be pulsed in a controlled mannerto avoid overlapping into readout periods of the image pixels in a pixelarray of the image sensor 214.

In one embodiment, the lumen waveguide 210 includes one or more opticalfibers. The optical fibers may be made of a low-cost material, such asplastic to allow for disposal of the lumen waveguide 210 and/or otherportions of an endoscope. In one embodiment, the lumen waveguide 210 isa single glass fiber having a diameter of 500 microns. The jumperwaveguide 206 may be permanently attached to the emitter 202. Forexample, a jumper waveguide 206 may receive light from an emitter withinthe emitter 202 and provide that light to the lumen waveguide 210 at thelocation of the connector 208. In one embodiment, the jumper waveguide106 includes one or more glass fibers. The jumper waveguide may includeany other type of waveguide for guiding light to the lumen waveguide210. The connector 208 may selectively couple the jumper waveguide 206to the lumen waveguide 210 and allow light within the jumper waveguide206 to pass to the lumen waveguide 210. In one embodiment, the lumenwaveguide 210 is directly coupled to a light source without anyintervening jumper waveguide 206.

The image sensor 214 includes a pixel array. In an embodiment, the imagesensor 214 includes two or more pixel arrays for generating athree-dimensional image. The image sensor 214 may constitute two moreimage sensors that each have an independent pixel array and can operateindependent of one another. The pixel array of the image sensor 214includes active pixels and optical black (“OB”) or optically blindpixels. The active pixels may be clear “color agnostic” pixels that arecapable of sensing imaging data for any wavelength of electromagneticradiation. The optical black pixels are read during a blanking period ofthe pixel array when the pixel array is “reset” or calibrated. In anembodiment, light is pulsed during the blanking period of the pixelarray when the optical black pixels are being read. After the opticalblack pixels have been read, the active pixels are read during a readoutperiod of the pixel array. The active pixels may be charged by theelectromagnetic radiation that is pulsed during the blanking period suchthat the active pixels are ready to be read by the image sensor duringthe readout period of the pixel array.

FIG. 2A is a schematic diagram of complementary system hardware such asa special purpose or general-purpose computer. Implementations withinthe scope of the present disclosure may also include physical and othernon-transitory computer readable media for carrying or storing computerexecutable instructions and/or data structures. Such computer readablemedia can be any available media that can be accessed by a generalpurpose or special purpose computer system. Computer readable media thatstores computer executable instructions are computer storage media(devices). Computer readable media that carry computer executableinstructions are transmission media. Thus, by way of example, and notlimitation, implementations of the disclosure can comprise at least twodistinctly different kinds of computer readable media: computer storagemedia (devices) and transmission media.

Computer storage media (devices) includes RAM, ROM, EEPROM, CD-ROM,solid state drives (“SSDs”) (e.g., based on RAM), Flash memory,phase-change memory (“PCM”), other types of memory, other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium which can be used to store desired program code means inthe form of computer executable instructions or data structures andwhich can be accessed by a general purpose or special purpose computer.

A “network” is defined as one or more data links that enable thetransport of electronic data between computer systems and/or modulesand/or other electronic devices. In an implementation, a sensor andcamera control unit may be networked to communicate with each other, andother components, connected over the network to which they areconnected. When information is transferred or provided over a network oranother communications connection (either hardwired, wireless, or acombination of hardwired or wireless) to a computer, the computerproperly views the connection as a transmission medium. Transmissionsmedia can include a network and/or data links, which can be used tocarry desired program code means in the form of computer executableinstructions or data structures and which can be accessed by a generalpurpose or special purpose computer. Combinations of the above shouldalso be included within the scope of computer readable media.

Further, upon reaching various computer system components, program codemeans in the form of computer executable instructions or data structuresthat can be transferred automatically from transmission media tocomputer storage media (devices) (or vice versa). For example, computerexecutable instructions or data structures received over a network ordata link can be buffered in RAM within a network interface module(e.g., a “NIC”), and then eventually transferred to computer system RAMand/or to less volatile computer storage media (devices) at a computersystem. RAM can also include solid state drives (SSDs or PCIx based realtime memory tiered storage, such as FusionIO). Thus, it should beunderstood that computer storage media (devices) can be included incomputer system components that also (or even primarily) utilizetransmission media.

Computer executable instructions comprise, for example, instructions anddata which, when executed by one or more processors, cause ageneral-purpose computer, special purpose computer, or special purposeprocessing device to perform a certain function or group of functions.The computer executable instructions may be, for example, binaries,intermediate format instructions such as assembly language, or evensource code. Although the subject matter has been described in languagespecific to structural features and/or methodological acts, it is to beunderstood that the subject matter defined in the appended claims is notnecessarily limited to the described features or acts described above.Rather, the described features and acts are disclosed as example formsof implementing the claims.

Those skilled in the art will appreciate that the disclosure may bepracticed in network computing environments with many types of computersystem configurations, including, personal computers, desktop computers,laptop computers, message processors, control units, camera controlunits, hand-held devices, hand pieces, multi-processor systems,microprocessor-based or programmable consumer electronics, network PCs,minicomputers, mainframe computers, mobile telephones, PDAs, tablets,pagers, routers, switches, various storage devices, and the like. Itshould be noted that any of the above-mentioned computing devices may beprovided by or located within a brick and mortar location. Thedisclosure may also be practiced in distributed system environmentswhere local and remote computer systems, which are linked (either byhardwired data links, wireless data links, or by a combination ofhardwired and wireless data links) through a network, both performtasks. In a distributed system environment, program modules may belocated in both local and remote memory storage devices.

Further, where appropriate, functions described herein can be performedin one or more of: hardware, software, firmware, digital components, oranalog components. For example, one or more application specificintegrated circuits (ASICs) or field programmable gate arrays (FPGAs)can be programmed to carry out one or more of the systems and proceduresdescribed herein. Certain terms are used throughout the followingdescription and Claims to refer to particular system components. As oneskilled in the art will appreciate, components may be referred to bydifferent names. This document does not intend to distinguish betweencomponents that differ in name, but not function.

FIG. 2A is a block diagram illustrating an example computing device 250.Computing device 250 may be used to perform various procedures, such asthose discussed herein. Computing device 250 can function as a server, aclient, or any other computing entity. Computing device 250 can performvarious monitoring functions as discussed herein, and can execute one ormore application programs, such as the application programs describedherein. Computing device 250 can be any of a wide variety of computingdevices, such as a desktop computer, a notebook computer, a servercomputer, a handheld computer, camera control unit, tablet computer andthe like.

Computing device 250 includes one or more processor(s) 252, one or morememory device(s) 254, one or more interface(s) 256, one or more massstorage device(s) 258, one or more Input/Output (I/O) device(s) 260, anda display device 280 all of which are coupled to a bus 262. Processor(s)252 include one or more processors or controllers that executeinstructions stored in memory device(s) 254 and/or mass storagedevice(s) 258. Processor(s) 252 may also include various types ofcomputer readable media, such as cache memory.

Memory device(s) 254 include various computer readable media, such asvolatile memory (e.g., random access memory (RAM) 264) and/ornonvolatile memory (e.g., read-only memory (ROM) 266). Memory device(s)254 may also include rewritable ROM, such as Flash memory.

Mass storage device(s) 258 include various computer readable media, suchas magnetic tapes, magnetic disks, optical disks, solid-state memory(e.g., Flash memory), and so forth. As shown in FIG. 2, a particularmass storage device is a hard disk drive 274. Various drives may also beincluded in mass storage device(s) 258 to enable reading from and/orwriting to the various computer readable media. Mass storage device(s)258 include removable media 276 and/or non-removable media.

I/O device(s) 260 include various devices that allow data and/or otherinformation to be input to or retrieved from computing device 250.Example I/O device(s) 260 include digital imaging devices,electromagnetic sensors and emitters, cursor control devices, keyboards,keypads, microphones, monitors or other display devices, speakers,printers, network interface cards, modems, lenses, CCDs or other imagecapture devices, and the like.

Display device 280 includes any type of device capable of displayinginformation to one or more users of computing device 250. Examples ofdisplay device 280 include a monitor, display terminal, video projectiondevice, and the like.

Interface(s) 256 include various interfaces that allow computing device250 to interact with other systems, devices, or computing environments.Example interface(s) 256 may include any number of different networkinterfaces 270, such as interfaces to local area networks (LANs), widearea networks (WANs), wireless networks, and the Internet. Otherinterface(s) include user interface 268 and peripheral device interface272. The interface(s) 256 may also include one or more user interfaceelements 268. The interface(s) 256 may also include one or moreperipheral interfaces such as interfaces for printers, pointing devices(mice, track pad, etc.), keyboards, and the like.

Bus 262 allows processor(s) 252, memory device(s) 254, interface(s) 256,mass storage device(s) 258, and I/O device(s) 260 to communicate withone another, as well as other devices or components coupled to bus 262.Bus 262 represents one or more of several types of bus structures, suchas a system bus, PCI bus, IEEE 1394 bus, USB bus, and so forth.

For purposes of illustration, programs and other executable programcomponents are shown herein as discrete blocks, although it isunderstood that such programs and components may reside at various timesin different storage components of computing device 250 and are executedby processor(s) 252. Alternatively, the systems and procedures describedherein can be implemented in hardware, or a combination of hardware,software, and/or firmware. For example, one or more application specificintegrated circuits (ASICs) or field programmable gate arrays (FPGAs)can be programmed to carry out one or more of the systems and proceduresdescribed herein.

FIG. 3A illustrates the operational cycles of a sensor used in rollingreadout mode or during the sensor readout 300. The frame readout periodmay start at and may be represented by vertical line 310. The readoutperiod 302 is represented by the diagonal or slanted line. The sensormay be read out on a row by row basis, the top of the downwards slantededge being the sensor top row 312 and the bottom of the downwardsslanted edge being the sensor bottom row 314. The time between the lastrow readout and the next readout period may be called the blankingperiod 316. It should be noted that some of the sensor pixel rows mightbe covered with a light shield (e.g., a metal coating or any othersubstantially black layer of another material type). These covered pixelrows may be referred to as optical black rows 318 and 320. Optical blackrows 318 and 320 may be used as input for correction algorithms. Asshown in FIG. 3A, these optical black rows 318 and 320 may be located onthe top of the pixel array or at the bottom of the pixel array or at thetop and the bottom of the pixel array.

FIG. 3B illustrates a process of controlling the amount ofelectromagnetic radiation, e.g., light, that is exposed to a pixel,thereby integrated or accumulated by the pixel. It will be appreciatedthat photons are elementary particles of electromagnetic radiation.Photons are integrated, absorbed, or accumulated by each pixel andconverted into an electrical charge or current. An electronic shutter orrolling shutter (shown by dashed line 322) may be used to start theintegration time by resetting the pixel. The light will then integrateuntil the next readout period. The position of the electronic shutter322 can be moved between two readout periods 302 to control the pixelsaturation for a given amount of light. It should be noted that thistechnique allows for a constant integration time between two differentlines but introduces a delay when moving from top to bottom rows.

FIG. 3C illustrates the case where the electronic shutter 322 has beenremoved. In this configuration, the integration of the incoming lightmay start during the readout period 302 and may end at the next readoutperiod 302, which also defines the start of the next integration.

FIG. 3D shows a configuration without an electronic shutter 322, butwith a controlled and pulsed light 330 during the blanking period 316.This ensures that all rows see the same light issued from the same lightpulse 330. In other words, each row will start its integration in a darkenvironment, which may be at the optical black back row 320 of read outframe (m) for a maximum light pulse width, and will then receive a lightstrobe and will end its integration in a dark environment, which may beat the optical black front row 318 of the next succeeding read out frame(m+1) for a maximum light pulse width. In the FIG. 3D example, the imagegenerated from the light pulse will be solely available during frame(m+1) readout without any interference with frame (m) and a frameimmediately following frame (m+1). Although not shown in FIG. 3D, framesfollowing frame (m+1) may be referred to as frames (m+2), (m+3), etc. Itshould be noted that the condition to have a light pulse to be read outonly in one frame and not interfere with neighboring frames is to havethe given light pulse firing during the blanking period 316. Because theoptical black rows 318, 320 are insensitive to light, the optical blackback rows 320 time of frame (m) and the optical black front rows 318time of frame (m+1) can be added to the blanking period 316 to determinethe maximum range of the firing time of the light pulse 330.

As illustrated in the FIG. 3A, a sensor may be cycled many times toreceive data for each pulsed color or wavelength (e.g., Red, Green,Blue, or other wavelength on the electromagnetic spectrum). Each cyclemay be timed. In an embodiment, the cycles may be timed to operatewithin an interval of 16.67 ms. In another embodiment, the cycles may betimed to operate within an interval of 8.3 ms. It will be appreciatedthat other timing intervals are contemplated by the disclosure and areintended to fall within the scope of this disclosure.

FIG. 4A graphically illustrates the operation of an embodiment of anelectromagnetic emitter. An emitter may be timed to correspond with thecycles of a sensor, such that electromagnetic radiation is emittedwithin the sensor operation cycle and/or during a portion of the sensoroperation cycle. FIG. 4A illustrates Pulse 1 at 402, Pulse 2 at 404, andPulse 3 at 406. In an embodiment, the emitter may pulse during thereadout period 302 of the sensor operation cycle. In an embodiment, theemitter may pulse during the blanking period 316 of the sensor operationcycle. In an embodiment, the emitter may pulse for a duration that isduring portions of two or more sensor operational cycles. In anembodiment, the emitter may begin a pulse during the blanking period316, or during the optical black portion 320 of the readout period 302,and end the pulse during the readout period 302, or during the opticalblack portion 318 of the readout period 302 of the next succeedingcycle. It will be understood that any combination of the above isintended to fall within the scope of this disclosure as long as thepulse of the emitter and the cycle of the sensor correspond.

FIG. 4B graphically represents varying the duration and magnitude of theemitted electromagnetic pulse (e.g., Pulse 1 at 412, Pulse 2 at 414, andPulse 3 at 416) to control exposure. An emitter having a fixed outputmagnitude may be pulsed during any of the cycles noted above in relationto FIGS. 3D and 4A for an interval to provide the needed electromagneticenergy to the pixel array. An emitter having a fixed output magnitudemay be pulsed at a longer interval of time, thereby providing moreelectromagnetic energy to the pixels or the emitter may be pulsed at ashorter interval of time, thereby providing less electromagnetic energy.Whether a longer or shorter interval time is needed depends upon theoperational conditions.

In contrast to adjusting the interval of time the emitter pulses a fixedoutput magnitude, the magnitude of the emission itself may be increasedto provide more electromagnetic energy to the pixels. Similarly,decreasing the magnitude of the pulse provides less electromagneticenergy to the pixels. It should be noted that an embodiment of thesystem may have the ability to adjust both magnitude and durationconcurrently, if desired. Additionally, the sensor may be adjusted toincrease its sensitivity and duration as desired for optimal imagequality. FIG. 4B illustrates varying the magnitude and duration of thepulses. In the illustration, Pulse 1 at 412 has a higher magnitude orintensity than either Pulse 2 at 414 or Pulse 3 at 416. Additionally,Pulse 1 at 412 has a shorter duration than Pulse 2 at 414 or Pulse 3 at416, such that the electromagnetic energy provided by the pulse isillustrated by the area under the pulse shown in the illustration. Inthe illustration, Pulse 2 at 414 has a relatively low magnitude orintensity and a longer duration when compared to either Pulse 1 at 412or Pulse 3 at 416. Finally, in the illustration, Pulse 3 at 416 has anintermediate magnitude or intensity and duration, when compared to Pulse1 at 412 and Pulse 2 at 414.

FIG. 5 is a graphical representation of an embodiment of the disclosurecombining the operational cycles, the electromagnetic emitter, and theemitted electromagnetic pulses of FIGS. 3A-3D and 4A to demonstrate theimaging system during operation in accordance with the principles andteachings of the disclosure. As can be seen in the figure, theelectromagnetic emitter pulses the emissions primarily during theblanking period 316 of the image sensor such that the pixels will becharged and ready to read during the readout period 302 of the imagesensor cycle. The dashed lines in FIG. 5 represent the pulses ofelectromagnetic radiation (from FIG. 4A). The pulses of electromagneticradiation are primarily emitted during the blanking period 316 of theimage sensor but may overlap with the readout period 302 of the imagesensor.

An exposure frame includes the data read by the pixel array of the imagesensor during a readout period 302. The exposure frame may be combinedwith an indication of what type of pulse was emitted by the emitterprior to the readout period 302. The combination of the exposure frameand the indication of the pulse type may be referred to as a dataset.Multiple exposure frames may be combined to generate a black-and-whiteor RGB color image. Additionally, hyperspectral, fluorescence, and/orlaser mapping imaging data may be overlaid on a black-and-white or RGBimage.

In an embodiment, an exposure frame is the data sensed by the pixelarray during the readout period 302 that occurs subsequent to a blankingperiod 316. The emission of electromagnetic radiation is emitted duringthe blanking period 316. In an embodiment, a portion of the emission ofelectromagnetic radiation overlaps the readout period 302. The blankingperiod 316 occurs when optical black pixels of the pixel array are beingread and the readout period 302 occurs when active pixels of the pixelarray are being read. The blanking period 316 may overlap the readoutperiod 302.

FIGS. 6A and 6B illustrate processes for recording an image frame.Multiple image frames may be strung together to generate a video stream.A single image frame may include data from multiple exposure frames,wherein an exposure frame is the data sensed by a pixel array subsequentto an emission of electromagnetic radiation. FIG. 6A illustrates atraditional process that is typically implemented with a color imagesensor having a color filter array (CFA) for filtering out certainwavelengths of light per pixel. FIG. 6B is a process that is disclosedherein and can be implemented with a monochromatic “color agnostic”image sensor that is receptive to all wavelengths of electromagneticradiation.

The process illustrated in FIG. 6A occurs from time t(0) to time t(1).The process begins with a white light emission 602 and sensing whitelight 604. The image is processed and displayed at 606 based on thesensing at 604.

The process illustrated in FIG. 6B occurs from time t(0) to time t(1).The process begins with an emission of green light 612 and sensingreflected electromagnetic radiation 614 subsequent to the emission ofgreen light 612. The process continues with an emission of red light 616and sensing reflected electromagnetic radiation 618 subsequent to theemission of red light 616. The process continues with an emission ofblue light 620 and sensing reflected electromagnetic radiation 622subsequent to the emission of blue light 620. The process continues withone or more emissions of a fluorescence excitation wavelengths 624 andsensing reflected electromagnetic energy 626 subsequent to each of theone or more emissions of fluorescence excitation wavelengths ofelectromagnetic radiation 624. The image is processed and displayed at628 based on each of the sensed reflected electromagnetic energyinstances 614, 618, 622, and 626.

The process illustrated in FIG. 6B provides a higher resolution imageand provides a means for generating an RGB image that further includesfluorescence imaging data. When partitioned spectrums of light are used,(as in FIG. 6B) a sensor can be made sensitive to all wavelengths ofelectromagnetic energy. In the process illustrated in FIG. 6B, themonochromatic pixel array is instructed that it is sensingelectromagnetic energy from a predetermined partition of the fullspectrum of electromagnetic energy in each cycle. Therefore, to form animage the sensor need only be cycled with a plurality of differingpartitions from within the full spectrum of light. The final image isassembled based on the multiple cycles. Because the image from eachcolor partition frame cycle has a higher resolution (compared with a CFApixel array), the resultant image created when the partitioned lightframes are combined also has a higher resolution. In other words,because each and every pixel within the array (instead of, at most,every second pixel in a sensor with a CFA) is sensing the magnitudes ofenergy for a given pulse and a given scene, just fractions of timeapart, a higher resolution image is created for each scene.

As can be seen graphically in the embodiments illustrated in FIGS. 6Aand 6B between times t(0) and t(1), the sensor for the partitionedspectrum system in FIG. 6B has cycled at least four times for every oneof the full spectrum system in FIG. 6A. In an embodiment, a displaydevice (LCD panel) operates at 50-60 frames per second. In such anembodiment, the partitioned light system in FIG. 6B may operate at200-240 frames per second to maintain the continuity and smoothness ofthe displayed video. In other embodiments, there may be differentcapture and display frame rates. Furthermore, the average capture ratecould be any multiple of the display rate.

In an embodiment, it may be desired that not all partitions berepresented equally within the system frame rate. In other words, notall light sources have to be pulsed with the same regularity so as toemphasize and de-emphasize aspects of the recorded scene as desired bythe users. It should also be understood that non-visible and visiblepartitions of the electromagnetic spectrum may be pulsed together withina system with their respective data value being stitched into the videooutput as desired for display to a user.

An embodiment may comprise a pulse cycle pattern as follows:

i. Green pulse;

ii. Red pulse;

iii. Blue pulse;

iv. Green pulse;

v. Red pulse;

vi. Blue pulse;

vii. Fluorescence excitation pulse;

viii. (Repeat)

As can be seen in the example, a fluorescence excitation partition maybe pulsed at a rate differing from the rates of the other partitionpulses. This may be done to emphasize a certain aspect of the scene,with the fluorescence imaging data simply being overlaid with the otherdata in the video output to make the desired emphasis. It should benoted that the addition of a fluorescence partition on top of the RED,GREEN, and BLUE partitions does not necessarily require the serializedsystem to operate at four times the rate of a full spectrum non-serialsystem because every partition does not have to be represented equallyin the pulse pattern. As seen in the embodiment, the addition of apartition pulse that is represented less in a pulse pattern(fluorescence excitation in the above example), would result in anincrease of less than 20% of the cycling speed of the sensor toaccommodate the irregular partition sampling.

In various embodiments, the pulse cycle pattern may further include anyof the following wavelengths in any suitable order. Such wavelengths maybe particularly suited for exciting a fluorescent reagent to generatefluorescence imaging data by sensing the relaxation emission of thefluorescent reagent based on a fluorescent reagent relaxation emission:

i. 770±20 nm;

ii. 770±10 nm;

iii. 770±5 nm;

iv. 790±20 nm;

v. 790±10 nm;

vi. 790±5 nm;

vii. 795±20 nm;

viii. 795±10 nm;

ix. 795±5 nm;

x. 815±20 nm;

xi. 815±10 nm;

xii. 815±5 nm;

xiii. 770 nm to 790 nm; and/or

xiv. 795 nm to 815 nm.

The partition cycles may be divided so as to accommodate or approximatevarious imaging and video standards. In an embodiment, the partitioncycles may comprise pulses of electromagnetic energy in the Red, Green,and Blue spectrum as follows as illustrated best in FIGS. 7A-7D. In FIG.7A, the different light intensities have been achieved by modulating thelight pulse width or duration within the working range shown by thevertical grey dashed lines. In FIG. 7B, the different light intensitieshave been achieved by modulating the light power or the power of theelectromagnetic emitter, which may be a laser or LED emitter, butkeeping the pulse width or duration constant. FIG. 7C shows the casewhere both the light power and the light pulse width are beingmodulated, leading to greater flexibility. The partition cycles may useCyan Magenta Yellow (CMY), infrared, ultraviolet, hyperspectral, andfluorescence using a non-visible pulse source mixed with visible pulsesources and any other color space required to produce an image orapproximate a desired video standard that is currently known or yet tobe developed. It should also be understood that a system may be able toswitch between the color spaces on the fly to provide the desired imageoutput quality.

In an embodiment using color spaces Green-Blue-Green-Red (as seen inFIG. 7D) it may be desirous to pulse the luminance components more oftenthan the chrominance components because users are generally moresensitive to light magnitude differences than to light colordifferences. This principle can be exploited using a mono-chromaticsensor as illustrated in FIG. 7D. In FIG. 7D, green, which contains themost luminance information, may be pulsed more often or with moreintensity in a (G-B-G-R-G-B-G-R . . . ) scheme to obtain the luminancedata. Such a configuration would create a video stream that hasperceptively more detail, without creating and transmittingunperceivable data.

In an embodiment, duplicating the pulse of a weaker partition may beused to produce an output that has been adjusted for the weaker pulse.For example, blue laser light is considered weak relative to thesensitivity of silicon-based pixels and is difficult to produce incomparison to the red or green light, and therefore may be pulsed moreoften during a frame cycle to compensate for the weakness of the light.These additional pulses may be done serially over time or by usingmultiple lasers that simultaneously pulse to produce the desiredcompensation effect. It should be noted that by pulsing during ablanking period (time during which the sensor is not reading out thepixel array), the sensor is insensitive to differences/mismatchesbetween lasers of the same kind and simply accumulates the light for thedesired output. In another embodiment, the maximum light pulse range maybe different from frame to frame. This is shown in FIG. 7E, where thelight pulses are different from frame to frame. The sensor may be builtto be able to program different blanking times with a repeating patternof two or three or four or n frames. In FIG. 7E, four different lightpulses are illustrated, and Pulse 1 may repeat for example after Pulse 4and may have a pattern of four frames with different blanking times.This technique can be used to place the most powerful partition on thesmallest blanking time and therefore allow the weakest partition to havewider pulse on one of the next frames without the need of increasing thereadout speed. The reconstructed frame can still have a regular patternfrom frame to frame as it is constituted of many pulsed frames.

FIG. 8 is a schematic diagram of a process flow 800 to be implemented bya controller and/or monochrome image signal processor (ISP) forgenerating a video stream having RGB images with fluorescence dataoverlaid thereon. The process flow 800 results in images havingincreased dynamic range and spatial resolution. The image signalprocessor (ISP) chain may be assembled for the purpose of generating RGBimage sequences from raw sensor data, yielded in the presence of theG-R-G-B-Fluorescence light pulsing scheme. In the process flow 800, thefirst stage is concerned with making corrections to account for anynon-idealities in the sensor technology for which it is most appropriateto work in the raw data domain. At the next stage, multiple exposureframes (for example, a green exposure frame 812 a, a red-blue exposureframe 812 b, and a fluorescence exposure frame 812 c) are bufferedbecause each final exposure frame derives data from multiple raw frames.The frame reconstruction at 814 proceeds by sampling data from a currentexposure frame and buffered exposure frames (see 812 a, 812 b, and/or812 c). The reconstruction process results in full color image frames inlinear RGB color space that includes fluorescence image data.

The process flow 800 includes receiving data from an image sensor at802. Sensor correction calculations are performed at 804. These sensorcorrection calculations can be used to determine statistics at 806 suchas autoexposure settings and wide dynamic range settings. The processflow 800 continues and wide dynamic range fusion is processed at 808.Wide dynamic range compression is processed at 810. The wide dynamicrange compression from 810 can be fed to generate the green exposureframe 812 a, the red-blue exposure frame 812 b, and/or the fluorescenceexposure frame 812 c. The process flow 800 continues and framereconstruction is processed at 814 and then color correction isprocessed at 816. The process flow 800 continues and an RGB(red-green-blue) image is converted to a YCbCr (luminance-chrominanceblue-chrominance red) image at 818. Edge enhancement is processed at 820and then the YCbCr image is converted back to an RGB image at 822.Scalars are processed at 824 and gamma is processed at 826. The video isthen exported at 828.

FIG. 9 illustrates a process flow 900 for applying the super resolution(SR) and color motion artifact correction (CMAC) processes to imagedata. The super resolution algorithm uses data from multiple sequentialexposure frames that are combined to generate individual image frameswith increased spatial resolution. The generation of the individualimage frames depends upon accurate motion detection within local regionsof the multiple exposure frames. In some implementations, the luminanceplane is the most critical plane for determining spatial resolution. Ifthe luminance plane is the most critical plane, then only the adjacentluminance exposure frames are combined in an embodiment. In the case ofred-green-blue pulsing according to an R-G-B-G pulsing schedule, onlyadjacent green exposure frames are combined to generate the individualimage frames having higher spatial resolution.

With respect to the discussions regarding FIG. 9, the super resolutionalgorithm is applied in the context of Y-Cb-Cr light pulsing. YCbCr is afamily of color spaces that can be used as part of the color imagepipeline in video and digital photography systems. Y′ is the luminancecomponent (may be referred to as the “luma” component) and representsthe “black-and-white” or achromatic portion of the image. Cb is theblue-difference chrominance component (may be referred to as the“chroma” component) and Cr is the red-difference chrominance component.The chrominance components represent the color information in the imageor video stream. Analog RGB image information can be converted intoluminance and chrominance digital image information because human visionhas finer spatial sensitivity to luminance (black-and-white) differencesthan chromatic (color) differences. Video and imaging systems cantherefore store and transmit chromatic information at lower resolutionand optimize perceived detail at a particular bandwidth. Y′ (with theprime notation) is distinguished from Y (without the prime notation),where Y is luminance and refers to light intensity. Y′CbCr color spacesare defined by a mathematical coordinate transformation from anassociated RGB color space. If the underlying RGB color space isabsolute, the Y′CbCr color space is an absolute color space as well.

The use of the super resolution algorithm as disclosed herein is notlimited to any particular pulsing scheme and can be applied to YCbCrpulsing or to RGB pulsing. The super resolution algorithm may further beapplied to hyperspectral and/or fluorescence image data. In anembodiment, the endoscopic imaging system disclosed herein pulses lightto generate at least four types of captured frames. The capturedexposure frames include a Y exposure frame that contains pure luminanceinformation, a Cb exposure frame which contains a linear sum of Y and Cbdata, and a Cr exposure frame which contains a linear sum of Y and Crdata. During frame reconstruction (i.e. color fusion). There may be onefull color image frame in the YCbCr color space that is generated foreach luminance exposure frame at the input. The luminance data may becombined with the chrominance data from the frame prior to and the framefollowing the luminance frame. Note that given this pulsing sequence,the position of the Cb frame with respect to the Y frame ping-pongsbetween the before and after slots for alternate Y cases, as does itscomplementary Cr component. Therefore, the data from each captured Cb orCr chrominance frame may be utilized in two resultant full-color imageframes. The minimum frame latency may be provided by performing thecolor fusion process during chrominance (Cb or Cr) frame capture.

The super resolution algorithm (see 906) enhances the resolution of animage frame by combining multiple exposure frames. Data from multiplesequential exposure frames is combined to increase the spatialresolution of the resultant image frame. The super resolution algorithmdepends on accurate motion detection within local regions of the sceneacross the multiple exposure frames. The super resolution algorithmcombines non-redundant information from the multiple exposure frames togenerate a high-resolution image frame. The non-redundant information inthe multiple exposure frames can be introduced by subpixel shiftsbetween the multiple exposure frames. The subpixel shifts may occur dueto uncontrolled motions by objects within the scene or by the imagingsystem itself. In an embodiment, the super resolution algorithm includesaligning the multiple exposure frames to pixel-level or subpixel-levelaccuracy and combining the multiple exposure frames into a highresolution image grid. There are numerous methods of applying a superresolution algorithm and any suitable method may be applied forcombining the multiple exposure frames.

In an embodiment, the super resolution algorithm relies on the luminanceplane to accurately detect motion within local regions of a scenecaptured by the multiple exposure frames. The luminance plane is themost critical for spatial resolution, and so the super resolutionalgorithm can be applied to luminance exposure frames in the case ofY-Cb-Cr light pulsing. In the case of R-G-B-G light pulsing, the superresolution algorithm can be applied to the green exposure frames.Embodiments of the disclosure are described in the context of theY-Cb-Cr light pulsing scheme. However, it should be appreciated that themethods and systems described herein are not restricted to the Y-Cb-Crpulsing scheme and can be applied to the R-G-B-G pulsing scheme. Whenthe methods and systems are applied to the R-G-B-G pulsing scheme, thegreen exposure frame takes the place of the luminance exposure frame,the red exposure frame takes the place of the Cr exposure frame, and theblue exposure frame takes the place of the Cb exposure frame.

Referring again to the process flow 900 illustrated in FIG. 9, data froma sensor is input at 902. Sensor correction 904 is performed on thesensor data. The super resolution (SR) and color motion artifactcorrection (CMAC) algorithms are implemented at 906. The SR and CMACprocesses 906 may be performed within the camera image signal processoron raw, captured sensor data. The SR and CMAC processes can be performedat 906 immediately after all digital sensor correction 904 processes arecompleted. The SR and CMAC processes 906 can be executed before thesensor data is fused into linear RGB or YCbCr space color images.Statistics can be exported at 908 to determine the appropriateautoexposure for the image.

A chrominance exposure frame 910 a and a luminance exposure frame 910 bare constructed. In an embodiment, a fluorescence exposure frame 910 cis also constructed. The luminance exposure frame 910 b is constructedbased on the Y frames in arrival order. The chrominance exposure frames910 a are constructed based on the Cb and Cr frames in arrival order.The number of frames processed by the super resolution algorithm is anoptional variable. The first-in-first-out depth of the luminanceexposure frame 910 b is normally odd and its size can be determinedbased on available processing, memory, memory-bandwidth, motiondetection precision, or acceptable latency considerations. The colormotion artifact correction process can be performed with the minimumfirst-in-first-out depth of three frames for Y and two frames for Cband/or Cr. The super resolution algorithm may generate better resolutionby the use of five luminance frames.

The super resolution process itself may involve combining data frommultiple luminance exposure frames into a central super-resolved frame,which is stationary with respect to the luminance first-in-first-out(may be referred to as the RY buffer). For each of the non-centralluminance buffers, an upscaled version is produced in which individualblocks are shifted according to their (x,y) motion vectors. Any pixelsat the upscaled resolution that are not filled after shifting are leftblank.

The image data is processed to implement frame reconstruction at 912 andedge enhancement at 914. The YCbCr image is converted to an RGB image at916. Statistics on the RGB image can be exported at 918 to determineappropriate white balance. The appropriate white balance is applied at920 and entered into the color correction matrix at 922. Scalars 924 andgamma 926 are determined and the video is exported out at 928. Theprocess flow 900 can be implemented in the camera image signal processorin real-time while image data is captured and received from the sensor(see 902).

During frame reconstruction 912, there may be one full color image framein YCbCr space generated for each luminance exposure frame. The datacaptured in the luminance exposure frame may be combined with data fromchrominance exposure frames captured before and after the luminanceexposure frame. Given this pulsing sequence, the position of the Cbexposure frame with respect to the luminance exposure frame may beadjusted to occur before or after the luminance exposure frame foralternate luminance cases. The same is true for the Cr exposure framewith respect to the luminance exposure frame. Therefore, the data fromeach captured Cb or Cr exposure frame is used in two resultant fullcolor images. The minimum frame latency may be provided by performingthe frame reconstruction 912 process during the Cb and Cr frame capture.

In an embodiment, two frame first-in-first-out (FIFO) flows areconstructed. One FIFO is constructed for luminance exposure frames inarrival order and another FIFO is constructed for Cb exposure frames andCr exposure frames. The number of frames to use for the super resolution(see 906) process is an optional variable. The luminance FIFO depth maybe odd, and its size may be determined by the available processing,memory, or memory bandwidth, or by motion detection precision oracceptable latency considerations. The color motion artifact correction(CMAC) at 906 may be performed with the minimum FIFO depth of threeluminance exposure frames and two chrominance exposure frames. For thesuper resolution algorithm, the use of five luminance exposure framesresults in improved resolution. On luminance exposure frames, thecurrent object frame is the central in the luminance FIFO. Onchrominance exposure frames the two chrominance exposure frames thatflank the central luminance exposure frame are adjusted to line upmotion to the central luminance exposure frame.

FIG. 10 is a schematic of an example pixel array 1000 that may be usedto implement the process flow 900 illustrated in FIG. 9. The pixel array1000 includes a block of luminance pixels 1004 for generating data for aY luminance exposure frame. The pixel array 1000 includes RY pixels 1002framing the block of luminance pixels 1004. The RY pixels 1002 arebuffered first-in-first-out pixels.

On a luminance exposure frame, the current object frame is the centralblock of luminance pixels 1004 in the first-in-first-out. On chrominanceframes, the Cb and Cr frames flank the central block of luminance pixels1004. This is adjusted to line up motion to the central block ofluminance pixels 1004 to detect motion.

The super resolution and CMAC algorithms (see 906) rely on motiondetection. In an embodiment, a motion detection method includes blockmatching which provides x and y motion vectors for small, independentblocks of pixels of configurable dimensions. There are other motiondetection algorithms that may be used in other implementations. Bockmatching offers advantages for simplicity of implementation andparticularly for real time processing in hardware. In an embodiment, atwo-stage match process is described which provides for a super resolvedframe with two times the pixel count in the x and y directions. Furtherstages may be added to increase the pixel count further. However, manymore buffered frames and computations would be required to make thisworthwhile. In an embodiment, in addition to the raw, buffered,luminance exposure frames disposed in the middle of the luminance FIFO(referred to as frame RY pixels) 1002, three two-times upscaled versionsof the middle block of luminance pixels 1004 are created. The middleblock of luminance pixels 1004 may be upscaled using bilinearinterpolation (referred to as buffer BL). In an additional exposureframe, the block of luminance pixels 1004 may be upscaled using bicubicinterpolation (referred to as buffer BC). In an additional exposureframe, the block of luminance pixels 1004 may be upscaled with nointerpolation such that the upscaled frame includes only zeros in theplace of empty pixels (referred to as NI). The bilinear interpolationmay be used in the block matching method. The no interpolation forms thebaseline for the super resolved frame. The bicubic interpolation mayserve as a fallback pixel source for unfilled pixels within the superresolved frame.

FIG. 11 illustrates a schematic of a pixel array 1100 with luminanceframe pixels 1104 disbursed within pixels frame BL 1102. For eachluminance exposure frame in the buffer, except for the frame RY pixels1002, the pixel array may be segmented into square blocks of somedimension as illustrated in FIG. 10. Each block is shifted around, onepixel at a time, in both x and y directions, within some defined rangeof shifts in both positive and negative directions. For each pixellocation, the pixel data may be compared to the equivalent block sittingin that location with the object frame RY pixels 1002. The x and yshifts encountered for the best match position become the recordedCartesian motion coordinates for all pixels within the block. Thisprocess is depicted in FIG. 11.

In the pixel array 1100, for each luminance exposure frame in thebuffer, except for RY, the pixel array 1000 shown in FIG. 10 may besegmented into square blocks of some dimension, (e.g. 4×4). Each blockis shifted around, one pixel at a time, in both x and y, within somedefined range of shifts in both positive and negative directions (e.g.+/−3 pixels). For each location within the pixel array, a pixel may becompared to an equivalent block sitting in that location with the objectframe, RY. The x and y shifts encountered for the best match positionbecome the recorded Cartesian motion coordinates for all pixels withinthe pixel array 1100. There are various ways to make the comparison anda relatively convenient metric is the modulus of the pixel differences,(i.e. between the stationary pixel in RY and the corresponding pixel inthe block under study), summed over all pixels in the pixel array 1100.The best match may be taken as the minimum of this value. It can also berecorded for each block as a matching quality metric, which may be usedto arbitrate between competing pixels during the spatial resolutionprocess.

There are various ways to make this comparison. In an embodiment, ametric is calculated based on the modulus of the pixel differences,i.e., between the stationary pixel in the frame RY pixels 1002 and thecorresponding pixels in the block under study, summed over all pixels inthe block. The best match may be taken as the minimum of this value. Thebest match can be recorded for each block as a matching quality metricthat may be used to arbitrate between competing pixels during the superresolution algorithm (see 906). Alternatively, the minimum sum ofsquared differences may be used as the matching metric. At this stage,each pixel within non-RY luminance frames has a motion estimate that isquantized at the captured resolution. In an implementation where 2×resolution is sought, the method includes comparing a block of pixelswithin the non-Y frames to the BL buffer. This begins from the bestshifted position according to the recorded motion vectors. Shifts areperformed by shifting one-half pixel in the positive and negativedirections to give a total of nine possible positions. A half pixel inthe luminance frame under study is one whole pixel with respect to BL.Of those nine possible pixel positions, the best match is againdetermined, and the recorded motion vector is adjusted accordingly. Ifthe motion vector at this stage has a half integer component, then themotion vector has the potential to enhance the resolution of theresultant image frame.

Motion vectors for the two luminance exposure frames flanking RY may besaved for the CMAC process. The CMAC process may be performed during thechrominance exposure frames. The super resolution process itself mayinclude combining data from multiple exposure frames in a central superresolved frame. The central super resolved frame is stationary withrespect to the RY buffer. For each of the non-central luminance buffersa 2× upscaled version is generated in which the individual blocks havebeen shifted according to their (x,y) motion vectors. Any pixels at the2× resolution that are not filled after shifting are left blank.

The basis of the super resolved frame is the NI buffer which is theupscaled version of RY with no interpolation. Three of every four pixelsin NI may be initially blank. The primary objective may be to fill thepixels with data from the upscaled and shifted luminance buffers. Oneapproach is to scan the pixels for the first match for each empty pixel.At the end, any pixels still blank may be filled in from the BC buffer.Another approach is to assess possible candidates and select the bestcandidate based on a parameter that has been logged as a motion estimatequality metric. An example of a motion estimate quality metric is theminimum sum of absolute differences for the originating block or somederivative thereof. Another approach is to combine all candidates insome way, e.g., average the candidates or perform a weighted averageaccording to a quality parameter. In such an approach, even non-zeropixels in NI can be substituted. The benefit of such an approach is thatin addition to enhancing the resolution, the net signal to noise ratiois also improved. Candidates with notably poor quality values can alsobe rejected.

Each pixel within non-RY, luminance frames, has a motion estimate thatis quantized at the captured resolution. If 2× super resolution issought, the next stage involves, for block of pixels within the non-RYframes, comparing to the BL buffer instead of the RY buffer. Startingfrom the best shifted position (according to the recorded motionvectors). Shifts can be performed by positive and negative half-pixel,giving a total of nine possible positions as shown in FIG. 11. Of thosenine possible pixel positions, the best match is again determined, andthe recorded motion vector is adjusted accordingly.

Motion vectors for the luminance frames flanking RY frames may be savedfor the color motion artifact correction (CMAC) process which occursduring the C frames. The basis of the super-resolved frame is the NIbuffer which is the upscaled version of RY with no interpolation. Threeout of every four pixels in NI may be initially blank, and the primaryobjective is to fill them with data from the upscaled & shiftedluminance buffers. At the end, any pixels which are still blank may befilled in from the BC buffer which is the bicubic interpolated versionof the central luminance frame. A more sophisticated approach to fillingmay be to assess all possible candidates and choose the best one basedon some parameter that has been logged as a motion estimate qualitymetric. An example of such a metric could be the minimum sum of absolutedifferences for the originating block, or some derivative thereof. Thisrequires at least one additional frame buffer per luminance frame.Alternatively, all candidates can be combined in some way, e.g. as anaverage which can be weighted according to a quality parameter.Candidates with notably poor quality values can also be rejectedaltogether.

FIG. 12 illustrates the issue of significant motion from frame to framewith framewise color modulation. FIG. 12 illustrates an example in whicha ball is traveling through the scene at a quicker rate than the rate ofcapture for the Cb exposure frame, the Y exposure frame, the Cr exposureframe, and the fluorescence exposure frame. The ball is moving on atrajectory across the scene during capture that results in differentpositions for the Y, Cb, Cr, and fluorescence exposure frames. The basisof the color motion artifact correction is to utilize the relativemotion estimation for adjacent luminance (Y) frames to predict themotion that occurred for the intermediate Cb, Cr, and fluorescenceexposure frames relative to the luminance frame.

In an embodiment, the motion vectors for adjacent luminance frames areassessed and divided by two. This assumes that any motion that hasoccurred from luminance frame to luminance frame is linear. If motionestimation is available for three or more luminance frames in additionto the object frame (RY), then bicubic interpolation may be employed fora more precise interpolation. The pixel shifting can take place eitherat the original or the doubled resolution following a bicubic upscale.Either way, after shifting, there are many void locations with variousrandom shapes and sizes which may be filled in to ensure good imagequality.

The application of motion information can be different for color motionartifact correction (CMAC) compared with super resolution. Superresolution uses a bicubic upscaled version of RY as a default, so theworst case is that a pixel void is filled by interpolation using thesixteen closest neighbors in the correct motion frame. For CMAC, theremay be no predicting the distance of the nearest filled neighbors suchthat the known information is limited to the original block searchdistance divided by two. Some means of interpolation are required tofill in the holes. One way to do this is for each missing pixel, findthe distance to the closest filled pixel in the positive and negative xand y directions, and then fill with an average level that has beenweighted according to the reciprocal of each distance.

FIG. 13 is a schematic diagram of a pattern reconstruction process. Theexample pattern illustrated in FIG. 13 includes Red, Green, Blue, andFluorescence Excitation pulses of light that each last a duration of T1.It should be appreciated that the pattern reconstruction processillustrated in FIG. 13 can also be applied to a Y-Cb-Cr-FluorescenceExcitation pulsing scheme. In various embodiments, the pulses of lightmay be of the same duration or of differing durations. The Red, Green,Blue, and Fluorescence exposure frames are combined to generate an RGBimage with fluorescence imaging data overlaid thereon. A single imageframe comprising a red exposure frame, a green exposure frame, a blueexposure frame, and a fluorescence exposure frame requires a time periodof 4*T1 to be generated. The time durations shown in FIG. 13 areillustrative only and may vary for different implementations. In otherembodiments, different pulsing schemes may be employed. For example,embodiments may be based on the timing of each color component or frame(T1) and the reconstructed frame having a period twice that of theincoming color frame (2×T1). Different frames within the sequence mayhave different frame periods and the average capture rate could be anymultiple of the final frame rate.

In an embodiment, the dynamic range of the system is increased byvarying the pixel sensitivities of pixels within the pixel array of theimage sensor. Some pixels may sense reflected electromagnetic radiationat a first sensitivity level, other pixels may sense reflectedelectromagnetic radiation at a second sensitivity level, and so forth.The different pixel sensitivities may be combined to increase thedynamic range provided by the pixel configuration of the image sensor.In an embodiment, adjacent pixels are set at different sensitivitiessuch that each cycle includes data produced by pixels that are more andless sensitive with respect to each other. The dynamic range isincreased when a plurality of sensitivities are recorded in a singlecycle of the pixel array. In an embodiment, wide dynamic range can beachieved by having multiple global TX, each TX firing only on adifferent set of pixels. For example, in global mode, a global TX1signal is firing a set 1 of pixels, a global TX2 signal is firing a set2 of pixel, a global TXn signal is firing a set n of pixels, and soforth.

FIGS. 14A-14C each illustrate a light source 1400 having a plurality ofemitters. The emitters include a first emitter 1402, a second emitter1404, and a third emitter 1406. Additional emitters may be included, asdiscussed further below. The emitters 1402, 1404, and 1406 may includeone or more laser emitters that emit light having different wavelengths.For example, the first emitter 1402 may emit a wavelength that isconsistent with a blue laser, the second emitter 1404 may emit awavelength that is consistent with a green laser, and the third emitter1406 may emit a wavelength that is consistent with a red laser. Forexample, the first emitter 1402 may include one or more blue lasers, thesecond emitter 1404 may include one or more green lasers, and the thirdemitter 1406 may include one or more red lasers. The emitters 1402,1404, 1406 emit laser beams toward a collection region 1408, which maybe the location of a waveguide, lens, or other optical component forcollecting and/or providing light to a waveguide, such as the jumperwaveguide 206 or lumen waveguide 210 of FIG. 2.

In an implementation, the emitters 1402, 1404, and 1406 emithyperspectral wavelengths of electromagnetic radiation. Certainhyperspectral wavelengths may pierce through tissue and enable a medicalpractitioner to “see through” tissues in the foreground to identifychemical processes, structures, compounds, biological processes, and soforth that are located behind the tissues in the foreground. Thehyperspectral wavelengths may be specifically selected to identify aspecific disease, tissue condition, biological process, chemicalprocess, type of tissue, and so forth that is known to have a certainspectral response.

In an implementation where a patient has been administered a reagent ordye to aid in the identification of certain tissues, structures,chemical reactions, biological processes, and so forth, the emitters1402, 1404, and 1406 may emit wavelength(s) for fluorescing the reagentsor dyes. Such wavelength(s) may be determined based on the reagents ordyes administered to the patient. In such an embodiment, the emittersmay need to be highly precise for emitting desired wavelength(s) tofluoresce or activate certain reagents or dyes.

In an implementation, the emitters 1402, 1404, and 1406 emit a laserscanning pattern for mapping a topology of a scene and/or forcalculating dimensions and distances between objects in the scene. In anembodiment, the endoscopic imaging system is used in conjunction withmultiple tools such as scalpels, retractors, forceps, and so forth. Insuch an embodiment, each of the emitters 1402, 1404, and 1406 may emit alaser scanning pattern such that a laser scanning pattern is projectedon to each tool individually. In such an embodiment, the laser scanningdata for each of the tools can be analyzed to identify distances betweenthe tools and other objects in the scene.

In the embodiment of FIG. 14B, the emitters 1402, 1404, 1406 eachdeliver laser light to the collection region 1408 at different angles.The variation in angle can lead to variations where electromagneticenergy is located in an output waveguide. For example, if the lightpasses immediately into a fiber bundle (glass or plastic) at thecollection region 1408, the varying angles may cause different amountsof light to enter different fibers. For example, the angle may result inintensity variations across the collection region 1408. Furthermore,light from the different emitters may not be homogenously mixed so somefibers may receive different amounts of light of different colors.Variation in the color or intensity of light in different fibers canlead to non-optimal illumination of a scene. For example, variations indelivered light or light intensities may result at the scene andcaptured images.

In one embodiment, an intervening optical element may be placed betweena fiber bundle and the emitters 1402, 1404, 1406 to mix the differentcolors (wavelengths) of light before entry into the fibers or otherwaveguide. Example intervening optical elements include a diffuser,mixing rod, one or more lenses, or other optical components that mix thelight so that a given fiber receive a same amount of each color(wavelength). For example, each fiber in the fiber bundle may have asame color. This mixing may lead to the same color in each fiber butmay, in some embodiments, still result in different total brightnessdelivered to different fibers. In one embodiment, the interveningoptical element may also spread out or even out the light over thecollection region so that each fiber carries the same total amount oflight (e.g., the light may be spread out in a top hat profile). Adiffuser or mixing rod may lead to loss of light.

Although the collection region 1408 is represented as a physicalcomponent in FIG. 14A, the collection region 1408 may simply be a regionwhere light from the emitters 1402, 1404, and 1406 is delivered. In somecases, the collection region 1408 may include an optical component suchas a diffuser, mixing rod, lens, or any other intervening opticalcomponent between the emitters 1402, 1404, 1406 and an output waveguide.

FIG. 14C illustrates an embodiment of a light source 1400 with emitters1402, 1404, 1406 that provide light to the collection region 1408 at thesame or substantially same angle. The light is provided at an anglesubstantially perpendicular to the collection region 1408. The lightsource 1400 includes a plurality of dichroic mirrors including a firstdichroic mirror 1410, a second dichroic mirror 1412, and a thirddichroic mirror 1414. The dichroic mirrors 1410, 1412, 1414 includemirrors that reflect a first wavelength of light but transmit (or aretransparent to) a second wavelength of light. For example, the thirddichroic mirror 1414 may reflect blue laser light provided by the thirdemitter, while being transparent to the red and green light provided bythe first emitter 1402 and the second emitter 1404, respectively. Thesecond dichroic mirror 1412 may be transparent to red light from thefirst emitter 1402, but reflective to green light from the secondemitter 1404. If other colors or wavelengths are included dichroicmirrors may be selected to reflect light corresponding to at least oneemitter and be transparent to other emitters. For example, the thirddichroic mirror 1414 reflect the light form the third emitter 1406 butis to emitters “behind” it, such as the first emitter 1402 and thesecond emitter 1404. In embodiments where tens or hundreds of emittersare present, each dichroic mirror may be reflective to a correspondingemitter and emitters in front of it while being transparent to emittersbehind it. This may allow for tens or hundreds of emitters to emitelectromagnetic energy to the collection region 1408 at a substantiallysame angle.

Because the dichroic mirrors allow other wavelengths to transmit or passthrough, each of the wavelengths may arrive at the collection region1408 from a same angle and/or with the same center or focal point.Providing light from the same angle and/or same focal/center point cansignificantly improve reception and color mixing at the collectionregion 1408. For example, a specific fiber may receive the differentcolors in the same proportions they were transmitted/reflected by theemitters 1402, 1404, 1406 and mirrors 1410, 1412, 1414. Light mixing maybe significantly improved at the collection region compared to theembodiment of FIG. 14B. In one embodiment, any optical componentsdiscussed herein may be used at the collection region 1408 to collectlight prior to providing it to a fiber or fiber bundle.

FIG. 14C illustrates an embodiment of a light source 1400 with emitters1402, 1404, 1406 that also provide light to the collection region 1408at the same or substantially same angle. However, the light incident onthe collection region 1408 is offset from being perpendicular. Angle1416 indicates the angle offset from perpendicular. In one embodiment,the laser emitters 1402, 1404, 1406 may have cross sectional intensityprofiles that are Gaussian. As discussed previously, improveddistribution of light energy between fibers may be accomplished bycreating a more flat or top-hat shaped intensity profile. In oneembodiment, as the angle 1416 is increased, the intensity across thecollection region 1408 approaches a top hat profile. For example, atop-hat profile may be approximated even with a non-flat output beam byincreasing the angle 1416 until the profile is sufficiently flat. Thetop hat profile may also be accomplished using one or more lenses,diffusers, mixing rods, or any other intervening optical componentbetween the emitters 1402, 1404, 1406 and an output waveguide, fiber, orfiber optic bundle.

FIG. 15 is a schematic diagram illustrating a single optical fiber 1502outputting via a diffuser 1504 at an output. In one embodiment, theoptical fiber 1502 has a diameter of 500 microns, a numerical apertureof 0.65, and emits a light cone 1506 of about 70 or 80 degrees without adiffuser 1504. With the diffuser 1504, the light cone 1506 may have anangle of about 110 or 120 degrees. The light cone 1506 may be a majorityof where all light goes and is evenly distributed. The diffuser 1504 mayallow for more even distribution of electromagnetic energy of a sceneobserved by an image sensor.

In one embodiment, the lumen waveguide 210 includes a single plastic orglass optical fiber of about 500 microns. The plastic fiber may be lowcost, but the width may allow the fiber to carry a sufficient amount oflight to a scene, with coupling, diffusion, or other losses. Forexample, smaller fibers may not be able to carry as much light or poweras a larger fiber. The lumen waveguide 210 may include a single or aplurality of optical fibers. The lumen waveguide 210 may receive lightdirectly from the light source or via a jumper waveguide. A diffuser maybe used to broaden the light output 206 for a desired field of view ofthe image sensor 214 or other optical components.

Although three emitters are shown in FIGS. 14A-14C, emitters numberingfrom one into the hundreds or more may be used in some embodiments. Theemitters may have different wavelengths or spectrums of light that theyemit, and which may be used to contiguously cover a desired portion ofthe electromagnetic spectrum (e.g., the visible spectrum as well asinfrared and ultraviolet spectrums). The emitters may be configured toemit visible light such as red light, green light, and blue light, andmay further be configured to emit hyperspectral emissions ofelectromagnetic radiation, fluorescence excitation wavelengths forfluorescing a reagent, and/or laser mapping patterns for calculatingparameters and distances between objects in a scene.

FIG. 16 illustrates a portion of the electromagnetic spectrum 1600divided into twenty different sub-spectrums. The number of sub-spectrumsis illustrative only. In at least one embodiment, the spectrum 1600 maybe divided into hundreds of sub-spectrums, each with a small waveband.The spectrum may extend from the infrared spectrum 1602, through thevisible spectrum 1604, and into the ultraviolet spectrum 1606. Thesub-spectrums each have a waveband 1608 that covers a portion of thespectrum 1600. Each waveband may be defined by an upper wavelength and alower wavelength.

Hyperspectral imaging includes imaging information from across theelectromagnetic spectrum 1600. A hyperspectral pulse of electromagneticradiation may include a plurality of sub-pulses spanning one or moreportions of the electromagnetic spectrum 1600 or the entirety of theelectromagnetic spectrum 1600. A hyperspectral pulse of electromagneticradiation may include a single partition of wavelengths ofelectromagnetic radiation. A resulting hyperspectral exposure frameincludes information sensed by the pixel array subsequent to ahyperspectral pulse of electromagnetic radiation. Therefore, ahyperspectral exposure frame may include data for any suitable partitionof the electromagnetic spectrum 1600 and may include multiple exposureframes for multiple partitions of the electromagnetic spectrum 1600. Inan embodiment, a hyperspectral exposure frame includes multiplehyperspectral exposure frames such that the combined hyperspectralexposure frame comprises data for the entirety of the electromagneticspectrum 1600.

In one embodiment, at least one emitter (such as a laser emitter) isincluded in a light source (such as the light sources 202, 1700) foreach sub-spectrum to provide complete and contiguous coverage of thewhole spectrum 1600. For example, a light source for providing coverageof the illustrated sub-spectrums may include at least 20 differentemitters, at least one for each sub-spectrum. In one embodiment, eachemitter covers a spectrum covering 40 nanometers. For example, oneemitter may emit light within a waveband from 500 nm to 540 nm whileanother emitter may emit light within a waveband from 540 nm to 580 nm.In another embodiment, emitters may cover other sizes of wavebands,depending on the types of emitters available or the imaging needs. Forexample, a plurality of emitters may include a first emitter that coversa waveband from 500 to 540 nm, a second emitter that covers a wavebandfrom 540 nm to 640 nm, and a third emitter that covers a waveband from640 nm to 650 nm. Each emitter may cover a different slice of theelectromagnetic spectrum ranging from far infrared, mid infrared, nearinfrared, visible light, near ultraviolet and/or extreme ultraviolet. Insome cases, a plurality of emitters of the same type or wavelength maybe included to provide sufficient output power for imaging. The numberof emitters needed for a specific waveband may depend on the sensitivityof a monochrome sensor to the waveband and/or the power outputcapability of emitters in that waveband.

The waveband widths and coverage provided by the emitters may beselected to provide any desired combination of spectrums. For example,contiguous coverage of a spectrum using very small waveband widths(e.g., 10 nm or less) may allow for highly selective hyperspectraland/or fluorescence imaging. The waveband widths may allow forselectively emitting the excitation wavelength(s) for one or moreparticular fluorescent reagents. Additionally, the waveband widths mayallow for selectively emitting certain partitions of hyperspectralelectromagnetic radiation for identifying specific structures, chemicalprocesses, tissues, biological processes, and so forth. Because thewavelengths come from emitters which can be selectively activated,extreme flexibility for fluorescing one or more specific fluorescentreagents during an examination can be achieved. Additionally, extremeflexibility for identifying one or more objects or processes by way ofhyperspectral imaging can be achieved. Thus, much more fluorescenceand/or hyperspectral information may be achieved in less time and withina single examination which would have required multiple examinations,delays because of the administration of dyes or stains, or the like.

FIG. 17 is a schematic diagram illustrating a timing diagram 1700 foremission and readout for generating an image. The solid line representsreadout (peaks 1702) and blanking periods (valleys) for capturing aseries of exposure frames 1704-1714. The series of exposure frames1704-1714 may include a repeating series of exposure frames which may beused for generating laser scanning, hyperspectral, and/or fluorescencedata that may be overlaid on an RGB video stream. In an embodiment, asingle image frame comprises information from multiple exposure frames,wherein one exposure frame includes red image data, another exposureframe includes green image data, and another exposure frame includesblue image data. Additionally, the single image frame may include one ormore of hyperspectral image data, fluorescence image data, and laserscanning data. The multiple exposure frames are combined to produce thesingle image frame. The single image frame is an RGB image withhyperspectral imaging data. The series of exposure frames include afirst exposure frame 1704, a second exposure frame 1706, a thirdexposure frame 1708, a fourth exposure frame 1710, a fifth exposureframe 1712, and an Nth exposure frame 1726.

Additionally, the hyperspectral image data, the fluorescence image data,and the laser scanning data can be used in combination to identifycritical tissues or structures and further to measure the dimensions ofthose critical tissues or structures. For example, the hyperspectralimage data may be provided to a corresponding system to identify certaincritical structures in a body such as a nerve, ureter, blood vessel,cancerous tissue, and so forth. The location and identification of thecritical structures may be received from the corresponding system andmay further be used to generate topology of the critical structuresusing the laser scanning data. For example, a corresponding systemdetermines the location of a cancerous tumor based on hyperspectralimaging data. Because the location of the cancerous tumor is known basedon the hyperspectral imaging data, the topology and distances of thecancerous tumor may then be calculated based on laser scanning data.This example may also apply when a cancerous tumor or other structure isidentified based on fluorescence imaging data.

In one embodiment, each exposure frame is generated based on at leastone pulse of electromagnetic energy. The pulse of electromagnetic energyis reflected and detected by an image sensor and then read out in asubsequent readout (1702). Thus, each blanking period and readoutresults in an exposure frame for a specific spectrum of electromagneticenergy. For example, the first exposure frame 1704 may be generatedbased on a spectrum of a first one or more pulses 1716, a secondexposure frame 1706 may be generated based on a spectrum of a second oneor more pulses 1718, a third exposure frame 1708 may be generated basedon a spectrum of a third one or more pulses 1720, a fourth exposureframe 1710 may be generated based on a spectrum of a fourth one or morepulses 1722, a fifth exposure frame 1712 may be generated based on aspectrum of a fifth one or more pulses 1724, and an Nth exposure frame1726 may be generated based on a spectrum of an Nth one or more pulses1726.

The pulses 1716-1726 may include energy from a single emitter or from acombination of two or more emitters. For example, the spectrum includedin a single readout period or within the plurality of exposure frames1704-1714 may be selected for a desired examination or detection of aspecific tissue or condition. According to one embodiment, one or morepulses may include visible spectrum light for generating an RGB or blackand white image while one or more additional pulses are emitted to sensea spectral response to a hyperspectral wavelength of electromagneticradiation. For example, pulse 1716 may include red light, pulse 1718 mayinclude blue light, and pulse 1720 may include green light while theremaining pulses 1722-1726 may include wavelengths and spectrums fordetecting a specific tissue type, fluorescing a reagent, and/or mappingthe topology of the scene. As a further example, pulses for a singlereadout period include a spectrum generated from multiple differentemitters (e.g., different slices of the electromagnetic spectrum) thatcan be used to detect a specific tissue type. For example, if thecombination of wavelengths results in a pixel having a value exceedingor falling below a threshold, that pixel may be classified ascorresponding to a specific type of tissue. Each frame may be used tofurther narrow the type of tissue that is present at that pixel (e.g.,and each pixel in the image) to provide a very specific classificationof the tissue and/or a state of the tissue (diseased/healthy) based on aspectral response of the tissue and/or whether a fluorescent reagent ispresent at the tissue.

The plurality of frames 1704-1714 is shown having varying lengths inreadout periods and pulses having different lengths or intensities. Theblanking period, pulse length or intensity, or the like may be selectedbased on the sensitivity of a monochromatic sensor to the specificwavelength, the power output capability of the emitter(s), and/or thecarrying capacity of the waveguide.

In one embodiment, dual image sensors may be used to obtainthree-dimensional images or video feeds. A three-dimensional examinationmay allow for improved understanding of a three-dimensional structure ofthe examined region as well as a mapping of the different tissue ormaterial types within the region.

In an example implementation, a fluorescent reagent is provided to apatient, and the fluorescent reagent is configured to adhere tocancerous cells. The fluorescent reagent is known to fluoresce whenradiated with a specific partition of electromagnetic radiation. Therelaxation wavelength of the fluorescent reagent is also known. In theexample implementation, the patient is imaged with an endoscopic imagingsystem as discussed herein. The endoscopic imaging system pulsespartitions of red, green, and blue wavelengths of light to generate anRGB video stream of the interior of the patient's body. Additionally,the endoscopic imaging system pulses the excitation wavelength ofelectromagnetic radiation for the fluorescent reagent that wasadministered to the patient. In the example, the patient has cancerouscells and the fluorescent reagent has adhered to the cancerous cells.When the endoscopic imaging system pulses the excitation wavelength forthe fluorescent reagent, the fluorescent reagent will fluoresce and emita relaxation wavelength. If the cancerous cells are present in the scenebeing imaged by the endoscopic imaging system, then the fluorescentreagent will also be present in the scene and will emit its relaxationwavelength after fluorescing due to the emission of the excitationwavelength. The endoscopic imaging system senses the relaxationwavelength of the fluorescent reagent and thereby senses the presence ofthe fluorescent reagent in the scene. Because the fluorescent reagent isknown to adhere to cancerous cells, the presence of the fluorescentreagent further indicates the presence of cancerous cells within thescene. The endoscopic imaging system thereby identifies the location ofcancerous cells within the scene. The endoscopic imaging system mayfurther emit a laser scanning pulsing scheme for generating a topologyof the scene and calculating dimensions for objects within the scene.The location of the cancerous cells (as identified by the fluorescenceimaging data) may be combined with the topology and dimensionsinformation calculated based on the laser scanning data. Therefore, theprecise location, size, dimensions, and topology of the cancerous cellsmay be identified. This information may be provided to a medicalpractitioner to aid in excising the cancerous cells. Additionally, thisinformation may be provided to a robotic surgical system to enable thesurgical system to excise the cancerous cells.

In a further example implementation, a patient is imaged with anendoscopic imaging system to identify quantitative diagnosticinformation about the patient's tissue pathology. In the example, thepatient is suspected or known to suffer from a disease that can betracked with hyperspectral imaging to observe the progression of thedisease in the patient's tissue. The endoscopic imaging system pulsespartitions of red, green, and blue wavelengths of light to generate anRGB video stream of the interior of the patient's body. Additionally,the endoscopic imaging system pulses one or more hyperspectralwavelengths of light that permit the system to “see through” sometissues and generate imaging of the tissue that is affected by thedisease. The endoscopic imaging system senses the reflectedhyperspectral electromagnetic radiation to generate hyperspectralimaging data of the diseased tissue, and thereby identifies the locationof the diseased tissue within the patient's body. The endoscopic imagingsystem may further emit a laser scanning pulsing scheme for generating atopology of the scene and calculating dimensions of objects within thescene. The location of the diseased tissue (as identified by thehyperspectral imaging data) may be combined with the topology anddimensions information that is calculated with the laser scanning data.Therefore, the precise location, size, dimensions, and topology of thediseased tissue can be identified. This information may be provided to amedical practitioner to aid in excising, imaging, or studying thediseased tissue. Additionally, this information may be provided to arobotic surgical system to enable the surgical system to excise thediseased tissue.

FIG. 18 is a schematic diagram of an imaging system 1800 having a singlecut filter. The system 1800 includes an endoscope 1806 or other suitableimaging device having a light source 1808 for use in a light deficientenvironment. The endoscope 1806 includes an image sensor 1804 and afilter 1802 for filtering out unwanted wavelengths of light or otherelectromagnetic radiation before reaching the image sensor 1804. Thelight source 1808 transmits light that may illuminate the surface 1812in a light deficient environment such as a body cavity. The light 1810is reflected off the surface 1812 and passes through the filter 1802before hitting the image sensor 1804.

The filter 1802 may be used in an implementation where a fluorescentreagent or dye has been administered. In such an embodiment, the lightsource 1808 emits the excitation wavelength for fluorescing thefluorescent reagent or dye. Commonly, the relaxation wavelength emittedby the fluorescent reagent or dye will be of a different wavelength thanthe excitation wavelength. The filter 1802 may be selected to filter outthe excitation wavelength and permit only the relaxation wavelength topass through the filter and be sensed by the image sensor 1804.

In one embodiment, the filter 1802 is configured to filter out anexcitation wavelength of electromagnetic radiation that causes a reagentor dye to fluoresce such that only the expected relaxation wavelength ofthe fluoresced reagent or dye is permitted to pass through the filter1802 and reach the image sensor 1804. In an embodiment, the filter 1802filters out at least a fluorescent reagent excitation wavelength between770 nm and 790 nm. In an embodiment, the filter 1802 filters out atleast a fluorescent reagent excitation wavelength between 795 nm and 815nm. In an embodiment, the filter 1802 filters out at least a fluorescentreagent excitation wavelength between 770 nm and 790 nm and between 795nm and 815 nm. In these embodiments, the filter 1802 filters out theexcitation wavelength of the reagent and permits only the relaxationwavelength of the fluoresced reagent to be read by the image sensor1804. The image sensor 1804 may be a wavelength-agnostic image sensorand the filter 1802 may be configured to permit the image sensor 1804 toonly receive the relaxation wavelength of the fluoresced reagent and notreceive the emitted excitation wavelength for the reagent. The datadetermined by the image sensor 1804 may then indicate a presence of acritical body structure, tissue, biological process, or chemical processas determined by a location of the reagent or dye.

The filter 1802 may further be used in an implementation where afluorescent reagent or dye has not been administered. The filter 1802may be selected to permit wavelengths corresponding to a desiredspectral response to pass through and be read by the image sensor 1804.The image sensor 1804 may be a monochromatic image sensor such thatpixels of the captured image that exceed a threshold or fall below athreshold may be characterized as corresponding to a certain spectralresponse or fluorescence emission. The spectral response or fluorescenceemission, as determined by the pixels captured by the image sensor 1804,may indicate the presence of a certain body tissue or structure, acertain condition, a certain chemical process, and so forth.

FIG. 19 is a schematic diagram of an imaging system 1900 having multiplecut filters. The system 1900 includes an endoscope 1906 or othersuitable imaging device having a light source 1908 for use in a lightdeficient environment. The endoscope 1906 includes an image sensor 1904and two filters 1902 a, 1902 b. It should be appreciated that inalternative embodiments, the system 1900 may include any number offilters, and the number of filters and the type of filters may beselected for a certain purpose e.g., for gathering imaging informationof a particular body tissue, body condition, chemical process, and soforth. The filters 1902 a, 1902 b are configured for preventing unwantedwavelengths of light or other electromagnetic radiation from beingsensed by the image sensor 1904. The filters 1902 a, 1902 b may beconfigured to filter out unwanted wavelengths from white light or otherelectromagnetic radiation that may be emitted by the light source 1908.

Further to the disclosure with respect to FIG. 19, the filters 1902 a,1902 b may be used in an implementation where a fluorescent reagent ordye has been administered. The filters 1902 a, 1902 b may be configuredfor blocking an emitted excitation wavelength for the reagent or dye andpermitting the image sensor 1904 to only read the relaxation wavelengthof the reagent or dye. Further, the filters 1902 a, 1902 b may be usedin an implementation where a fluorescent reagent or dye has not beenadministered. In such an implementation, the filters 1902 a, 1902 b maybe selected to permit wavelengths corresponding to a desired spectralresponse to pass through and be read by the image sensor 1904.

The multiple filters 1902 a, 1902 b may each be configured for filteringout a different range of wavelengths of the electromagnetic spectrum.For example, one filter may be configured for filtering out wavelengthslonger than a desired wavelength range and the additional filter may beconfigured for filtering out wavelengths shorter than the desiredwavelength range. The combination of the two or more filters may resultin only a certain wavelength or band of wavelengths being read by theimage sensor 1904.

In an embodiment, the filters 1902 a, 1902 b are customized such thatelectromagnetic radiation between 513 nm and 545 nm contacts the imagesensor 1904. In an embodiment, the filters 1902 a, 1902 b are customizedsuch that electromagnetic radiation between 565 nm and 585 nm contactsthe image sensor 1904. In an embodiment, the filters 1902 a, 1902 b arecustomized such that electromagnetic radiation between 900 nm and 1000nm contacts the image sensor 1904. In an embodiment, the filters 1902 a,1902 b are customized such that electromagnetic radiation between 425 nmand 475 nm contacts the image sensor 1904. In an embodiment, the filters1902 a, 1902 b are customized such that electromagnetic radiationbetween 520 nm and 545 nm contacts the image sensor 1904. In anembodiment, the filters 1902 a, 1902 b are customized such thatelectromagnetic radiation between 625 nm and 645 nm contacts the imagesensor 1904. In an embodiment, the filters 1902 a, 1902 b are customizedsuch that electromagnetic radiation between 760 nm and 795 nm contactsthe image sensor 1904. In an embodiment, the filters 1902 a, 1902 b arecustomized such that electromagnetic radiation between 795 nm and 815 nmcontacts the image sensor 1904. In an embodiment, the filters 1902 a,1902 b are customized such that electromagnetic radiation between 370 nmand 420 nm contacts the image sensor 1904. In an embodiment, the filters1902 a, 1902 b are customized such that electromagnetic radiationbetween 600 nm and 670 nm contacts the image sensor 1904. In anembodiment, the filters 1902 a, 1902 b are configured for permittingonly a certain fluorescence relaxation emission to pass through thefilters 1902 a, 1902 b and contact the image sensor 1904.

In an embodiment, the system 1900 includes multiple image sensors 1904and may particularly include two image sensors for use in generating athree-dimensional image. The image sensor(s) 1904 may becolor/wavelength agnostic and configured for reading any wavelength ofelectromagnetic radiation (light 1910) that is reflected off the surface1912. In an embodiment, the image sensors 1904 are each color dependentor wavelength dependent and configured for reading electromagneticradiation of a particular wavelength (light 1910) that is reflected offthe surface 1912 and back to the image sensors 1904. Alternatively, theimage sensor 1904 may include a single image sensor with a plurality ofdifferent pixel sensors configured for reading different wavelengths orcolors of light, such as a Bayer filter color filter array.Alternatively, the image sensor 1904 may include one or more coloragnostic image sensors that may be configured for reading differentwavelengths of electromagnetic radiation according to a pulsing schedulesuch as those illustrated in FIGS. 5-7E, for example.

FIGS. 20A and 20B illustrate a perspective view and a side view,respectively, of an implementation of a monolithic sensor 2000 having aplurality of pixel arrays for producing a three-dimensional image inaccordance with the teachings and principles of the disclosure. Such animplementation may be desirable for three-dimensional image capture,wherein the two-pixel arrays 2002 and 2004 may be offset during use. Inanother implementation, a first pixel array 2002 and a second pixelarray 2004 may be dedicated to receiving a predetermined range of wavelengths of electromagnetic radiation, wherein the first pixel array isdedicated to a different range of wavelength electromagnetic radiationthan the second pixel array.

FIGS. 21A and 21B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor 2100 built on aplurality of substrates. As illustrated, a plurality of pixel columns2104 forming the pixel array are located on the first substrate 2102 anda plurality of circuit columns 2108 are located on a second substrate2106. Also illustrated in the figure are the electrical connection andcommunication between one column of pixels to its associated orcorresponding column of circuitry. In one implementation, an imagesensor, which might otherwise be manufactured with its pixel array andsupporting circuitry on a single, monolithic substrate/chip, may havethe pixel array separated from all or a majority of the supportingcircuitry. The disclosure may use at least two substrates/chips, whichwill be stacked together using three-dimensional stacking technology.The first 2102 of the two substrates/chips may be processed using animage CMOS process. The first substrate/chip 2102 may be comprisedeither of a pixel array exclusively or a pixel array surrounded bylimited circuitry. The second or subsequent substrate/chip 2106 may beprocessed using any process and does not have to be from an image CMOSprocess. The second substrate/chip 2106 may be, but is not limited to, ahighly dense digital process to integrate a variety and number offunctions in a very limited space or area on the substrate/chip, or amixed-mode or analog process to integrate for example precise analogfunctions, or a RF process to implement wireless capability, or MEMS(Micro-Electro-Mechanical Systems) to integrate MEMS devices. The imageCMOS substrate/chip 2102 may be stacked with the second or subsequentsubstrate/chip 2106 using any three-dimensional technique. The secondsubstrate/chip 2106 may support most, or a majority, of the circuitrythat would have otherwise been implemented in the first image CMOS chip2102 (if implemented on a monolithic substrate/chip) as peripheralcircuits and therefore have increased the overall system area whilekeeping the pixel array size constant and optimized to the fullestextent possible. The electrical connection between the twosubstrates/chips may be done through interconnects, which may be wirebonds, bump and/or TSV (Through Silicon Via).

FIGS. 22A and 22B illustrate a perspective view and a side view,respectively, of an implementation of an imaging sensor 2200 having aplurality of pixel arrays for producing a three-dimensional image. Thethree-dimensional image sensor may be built on a plurality of substratesand may comprise the plurality of pixel arrays and other associatedcircuitry, wherein a plurality of pixel columns 2204 a forming the firstpixel array and a plurality of pixel columns 2204 b forming a secondpixel array are located on respective substrates 2202 a and 2202 b,respectively, and a plurality of circuit columns 2208 a and 2208 b arelocated on a separate substrate 2206. Also illustrated are theelectrical connections and communications between columns of pixels toassociated or corresponding column of circuitry.

The plurality of pixel arrays may sense information simultaneously andthe information from the plurality of pixel arrays may be combined togenerate a three-dimensional image. In an embodiment, an endoscopicimaging system includes two or more pixel arrays that can be deployed togenerate three-dimensional imaging. The endoscopic imaging system mayinclude an emitter for emitting pulses of electromagnetic radiationduring a blanking period of the pixel arrays. The pixel arrays may besynced such that the optical black pixels are read (i.e., the blankingperiod occurs) at the same time for the two or more pixel arrays. Theemitter may emit pulses of electromagnetic radiation for charging eachof the two or more pixel arrays. The two or more pixel arrays may readtheir respective charged pixels at the same time such that the readoutperiods for the two or more pixel arrays occur at the same time or atapproximately the same time. In an embodiment, the endoscopic imagingsystem includes multiple emitters that are each individual synced withone or more pixel arrays of a plurality of pixel arrays. Informationfrom a plurality of pixel arrays may be combined to generatethree-dimensional image frames and video streams.

It will be appreciated that the teachings and principles of thedisclosure may be used in a reusable device platform, a limited usedevice platform, a re-posable use device platform, or a singleuse/disposable device platform without departing from the scope of thedisclosure. It will be appreciated that in a re-usable device platforman end-user is responsible for cleaning and sterilization of the device.In a limited use device platform, the device can be used for somespecified amount of times before becoming inoperable. Typical new deviceis delivered sterile with additional uses requiring the end-user toclean and sterilize before additional uses. In a re-posable use deviceplatform, a third-party may reprocess the device (e.g., cleans, packagesand sterilizes) a single-use device for additional uses at a lower costthan a new unit. In a single use/disposable device platform a device isprovided sterile to the operating room and used only once before beingdisposed of.

EXAMPLES

The following examples pertain to preferred features of furtherembodiments:

Example 1 is a method. The method includes actuating an emitter to emita plurality of pulses of electromagnetic radiation. The method includessensing reflected electromagnetic radiation resulting from the pluralityof pulses of electromagnetic radiation with a pixel array of an imagesensor to generate a plurality of exposure frames. The method includesdetecting motion across two or more sequential exposure frames of theplurality of exposure frames. The method includes compensating for thedetected motion. The method includes combining the two or moresequential exposure frames to generate an image frame. The method issuch that at least a portion of the plurality of pulses ofelectromagnetic radiation emitted by the emitter comprises one or moreof: electromagnetic radiation having a wavelength from about 770 nm toabout 790 nm.

Example 2 is a method as in Example 1, wherein compensating for thedetected motion comprises: upscaling a first exposure frame of the twoor more sequential exposure frames using interpolation to generate afirst upscaled frame; upscaling the first exposure frame without usinginterpolation to generate a second upscaled frame, wherein the secondupscaled frame comprises a first set of empty pixels; and filling in thefirst set of empty pixels of the second upscaled frame with pixel datafrom the first upscaled frame.

Example 3 is a method as in any of Examples 1-2, wherein compensatingfor the detected motion further comprises: upscaling a second exposureframe of the two or more sequential exposure frames to generate a thirdupscaled frame; and filling in a second set of empty pixels in thesecond upscaled frame with pixel data from the third upscaled frame.

Example 4 is a method as in any of Examples 1-3, wherein the two or moresequential exposure frames comprises a red exposure frame, a greenexposure frame, and a blue exposure frame, and wherein combining the twoor more sequential exposure frames to generate the image frame comprisesgenerating a Red Green Blue (“RGB”) image frame.

Example 5 is a method as in any of Examples 1-4, wherein the two or moresequential exposure frames comprises a luminance (Y) exposure frame, achrominance blue (Cb) exposure frame, and a chrominance red (Cr)exposure frame, and wherein combining the two or more sequentialexposure frames to generate the image frame comprises generating a YCbCrimage frame.

Example 6 is a method as in any of Examples 1-5, wherein sensing thereflected electromagnetic radiation comprises: generating a firstexposure frame based on a pulse of electromagnetic radiation of a firstcolor partition; generating a second exposure frame based on a pulse ofelectromagnetic radiation of a second color partition; and generating athird exposure frame based on a pulse of electromagnetic radiation ofthe first color partition; wherein the second exposure frame is capturedbetween the first exposure frame and the third exposure frame; whereindetecting motion across the two or more sequential exposure framescomprises calculating a relative motion estimate based on the firstexposure frame and the third exposure frame using block matching; andwherein compensating for the detected motion comprises generating amotion compensated frame for the second exposure frame based on therelative motion estimate.

Example 7 is a method as in any of Examples 1-6, further comprising:determining a first motion vector for the first exposure frame and asecond motion vector for the second exposure frame; and shifting a blockof pixels in the first exposure frame by the first motion vector.

Example 8 is a method as in any of Examples 1-7, further comprising:performing bilinear interpolation on luminance data in the two or moresequential exposure frames to generate a first upscaled dataset;performing bicubic interpolation on the luminance data to generate asecond upscaled dataset; and calculating a baseline with nointerpolation of the luminance data to generate a third upscaleddataset.

Example 9 is a method as in any of Examples 1-8, wherein detectingmotion across two or more sequential exposure frames comprises one ormore of: segmenting data sensed by the pixel array into segments ofpixels and nearest neighboring exposure frames; shifting each segment ofpixels in the x direction and comparing with a neighboring exposureframe at a same resolution to identify motion of an object being imagedin the x direction; shifting each segment of pixels in the x directionin sub-pixel increments and comparing to the first upscaled dataset toidentify motion of the object being imaged in the x direction withincreased precision; shifting each segment of pixels in the y directionand comparing with a neighboring exposure frame to identify motion of anobject being imaged in the y direction; or shifting each segment ofpixels in the y direction in sub-pixel increments and comparing to thefirst upscaled dataset to identify motion of the object being imaged inthe y direction with increased precision.

Example 10 is a method as in any of Examples 1-9, wherein sensing thereflected electromagnetic radiation comprises sensing during a readoutperiod of the pixel array, wherein the readout period is a duration oftime when active pixels in the pixel array are read.

Example 11 is a method as in any of Examples 1-10, wherein actuating theemitter comprises actuating the emitter to emit, during a pulseduration, a plurality of sub-pulses of electromagnetic radiation havinga sub-duration shorter than the pulse duration.

Example 12 is a method as in any of Examples 1-11, wherein actuating theemitter comprises actuating the emitter to emit two or more wavelengthssimultaneously as a single pulse or a single sub-pulse.

Example 13 is a method as in any of Examples 1-12, wherein sensing thereflected electromagnetic radiation comprises generating a fluorescenceexposure frame, and wherein the method further comprises providing thefluorescence exposure frame to a corresponding system that determines alocation of a critical tissue structure within a scene based on thefluorescence exposure frame.

Example 14 is a method as in any of Examples 1-13, further comprising:receiving the location of the critical tissue structure from thecorresponding system; generating an overlay frame comprising thelocation of the critical tissue structure; and combining the overlayframe with a color image frame depicting the scene to indicate thelocation of the critical tissue structure within the scene.

Example 15 is a method as in any of Examples 1-14, wherein the criticaltissue structure comprises one or more of a nerve, a ureter, a bloodvessel, an artery, a blood flow, or a tumor.

Example 16 is a method as in any of Examples 1-15, further comprisingsynchronizing timing of the plurality of pulses of electromagneticradiation to be emitted during a blanking period of the image sensor,wherein the blanking period corresponds to a time between a readout of alast row of active pixels in the pixel array and a beginning of a nextsubsequent readout of active pixels in the pixel array.

Example 17 is a method as in any of Examples 1-16, wherein the two ormore sequential exposure frames are captured sequentially in time basedon two or more pulses of electromagnetic radiation emitted by theemitter sequentially in time.

Example 18 is a method as in any of Examples 1-17, wherein sensing thereflected electromagnetic radiation comprises sensing with a first pixelarray and a second pixel array such that a three-dimensional image canbe generated based on the sensed reflected electromagnetic radiation.

Example 19 is a method as in any of Examples 1-18, wherein actuating theemitter comprises actuating the emitter to emit a sequence of pulses ofelectromagnetic radiation repeatedly sufficient for generating a videostream comprising a plurality of image frames, wherein each image framein the video stream comprises data from a plurality of exposure frames,and wherein each of the exposure frames corresponds to a pulse ofelectromagnetic radiation.

Example 20 is a method as in any of Examples 1-19, wherein at least aportion of the plurality of pulses of electromagnetic radiation emittedby the emitter is an excitation wavelength for fluorescing a reagent,and wherein at least a portion of the reflected electromagneticradiation sensed by the pixel array is a relaxation wavelength of thereagent.

Example 21 is a system. The system includes an emitter for emitting aplurality of pulses of electromagnetic radiation. The system includes animage sensor comprising a pixel array for sensing reflectedelectromagnetic radiation to generate a plurality of exposure frames.The system includes one or more processors configurable to executeinstructions stored in non-transitory computer readable storage media,the instructions comprising: detecting motion across two or moresequential exposure frames of the plurality of exposure frames;compensating for the detection motion; and combining the two or moresequential exposure frames to generate an image frame; wherein at leasta portion of the pulses of electromagnetic radiation emitted by theemitter comprises one or more of: electromagnetic radiation having awavelength from about 770 nm to about 790 nm.

Example 22 is a system as in Example 21, wherein the instructions aresuch that compensating for the detected motion comprises: upscaling afirst exposure frame of the two or more sequential exposure frames usinginterpolation to generate a first upscaled frame; upscaling the firstexposure frame without using interpolation to generate a second upscaledframe, wherein the second upscaled frame comprises a first set of emptypixels; filling in the first set of empty pixels of the second upscaledframe with pixel data from the first upscaled frame; upscaling a secondexposure frame of the two or more sequential exposure frames to generatea third upscaled frame; and filling in a second set of empty pixels inthe second upscaled frame with pixel data from the third upscaled frame.

Example 23 is a system as in any of Examples 21-22, wherein one or moreof: the two or more sequential exposure frames comprises a luminance (Y)exposure frame, a chrominance blue (Cb) exposure frame, and achrominance red (Cr) exposure frame, and wherein combining the two ormore sequential exposure frames to generate the image frame comprisesgenerating a YCbCr image frame; or the two or more sequential exposureframes comprises a red exposure frame, a green exposure frame, and ablue exposure frame, and wherein combining the two or more sequentialexposure frames to generate the image frame comprises generating a RedGreen Blue (“RGB”) image frame.

Example 24 is a system as in any of Examples 21-23, wherein the imagesensor is configured to: generate a first exposure frame based on apulse of electromagnetic radiation of a first color partition; generatea second exposure frame based on a pulse of electromagnetic radiation ofa second color partition; and generate a third exposure frame based on apulse of electromagnetic radiation of the first color partition; whereinthe second exposure frame is captured between the first exposure frameand the third exposure frame; wherein the instructions are such thatdetecting motion across the two or more sequential exposure framescomprises calculating a relative motion estimate based on the firstexposure frame and the third exposure frame using block matching; andwherein the instructions are such that compensating for the detectedmotion comprises generating a motion compensated frame for the secondexposure frame based on the relative motion estimate.

Example 25 is a system as in any of Examples 21-24, wherein at least aportion of the pulses of electromagnetic radiation emitted by theemitter results in a fluorescence exposure frame created by the imagesensor, and wherein the instructions further comprise providing thefluorescence exposure frame to a corresponding system that determines alocation of a critical tissue structure within a scene based on thefluorescence exposure frame.

Example 26 is a system as in any of Examples 21-25, wherein theinstructions further comprise: receiving the location of the criticaltissue structure from the corresponding system; generating an overlayframe comprising the location of the critical tissue structure; andcombining the overlay frame with a color image frame depicting the sceneto indicate the location of the critical tissue structure within thescene.

Example 27 is a system as in any of Examples 21-26, wherein the criticaltissue structure comprises one or more of a nerve, a ureter, a bloodvessel, an artery, a blood flow, or a tumor.

Example 28 is a system as in any of Examples 21-27, wherein the imagesensor comprises a first image sensor and a second image sensor suchthat the image sensor can generate a three-dimensional image.

Example 29 is a system as in any of Examples 21-28, further comprising apolarization filter located in a path of the pulses of electromagneticradiation emitted by the emitter.

Example 30 is a system as in any of Examples 21-29, further comprising afilter that filters electromagnetic radiation having a wavelength fromabout 770 nm to about 790 nm.

Example 31 is means for performing any of the method steps recited inExamples 1-20.

It will be appreciated that various features disclosed herein providesignificant advantages and advancements in the art. The following claimsare exemplary of some of those features.

In the foregoing Detailed Description of the Disclosure, variousfeatures of the disclosure are grouped together in a single embodimentfor the purpose of streamlining the disclosure. This method ofdisclosure is not to be interpreted as reflecting an intention that theclaimed disclosure requires more features than are expressly recited ineach claim. Rather, inventive aspects lie in less than all features of asingle foregoing disclosed embodiment.

It is to be understood that any features of the above-describedarrangements, examples, and embodiments may be combined in a singleembodiment comprising a combination of features taken from any of thedisclosed arrangements, examples, and embodiments.

It is to be understood that the above-described arrangements are onlyillustrative of the application of the principles of the disclosure.Numerous modifications and alternative arrangements may be devised bythose skilled in the art without departing from the spirit and scope ofthe disclosure and the appended claims are intended to cover suchmodifications and arrangements.

Thus, while the disclosure has been shown in the drawings and describedabove with particularity and detail, it will be apparent to those ofordinary skill in the art that numerous modifications, including, butnot limited to, variations in size, materials, shape, form, function andmanner of operation, assembly and use may be made without departing fromthe principles and concepts set forth herein.

The foregoing description has been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the disclosure to the precise form disclosed. Many modificationsand variations are possible in light of the above teaching. Further, itshould be noted that any or all the aforementioned alternateimplementations may be used in any combination desired to formadditional hybrid implementations of the disclosure.

Further, although specific implementations of the disclosure have beendescribed and illustrated, the disclosure is not to be limited to thespecific forms or arrangements of parts so described and illustrated.The scope of the disclosure is to be defined by the claims appendedhereto, any future claims submitted here and in different applications,and their equivalents.

What is claimed is:
 1. A method comprising: actuating an emitter to emita plurality of pulses of electromagnetic radiation, wherein the emittercomprises a plurality of electromagnetic sources; sensing reflectedelectromagnetic radiation resulting from the plurality of pulses ofelectromagnetic radiation with a pixel array of an image sensor togenerate a plurality of frames, wherein the plurality of framescomprises a fluorescence exposure frame resulting from an emission bythe emitter of a fluorescence excitation wavelength having a wavelengthfrom 770 nm to 795 nm; identifying a luminance plane in each of a firstframe of the plurality of frames and a second frame of the plurality offrames that is subsequent to the first frame; detecting motion acrossthe first frame and the second frame of the plurality of frames based onthe luminance planes from each of the first frame and the second frame;calculating motion in the fluorescence exposure frame based on thedetected motion in the luminance planes from each of the first frame andthe second frame, wherein the fluorescence exposure frame is generatedbetween the first frame and the second frame; correcting thefluorescence exposure frame based on the calculated motion; andcombining the plurality of frames, after correcting the fluorescenceexposure frame for the calculated motion, to provide a color image framewith fluorescence image data.
 2. The method of claim 1, furthercomprising correcting detected motion in the plurality of frames by:upscaling the first frame of the plurality of frames using interpolationto generate a first upscaled frame; upscaling the first frame withoutusing interpolation to generate a second upscaled frame, wherein thesecond upscaled frame comprises a first set of empty pixels; and fillingin the first set of empty pixels of the second upscaled frame with pixeldata from the first upscaled frame.
 3. The method of claim 2, furthercomprising: upscaling a second exposure frame of the plurality of framesto generate a third upscaled frame; and filling in a second set of emptypixels in the second upscaled frame with pixel data from the thirdupscaled frame.
 4. The method of claim 1, wherein the plurality offrames comprises a luminance (Y) exposure frame, a chrominance blue (Cb)exposure frame, and a chrominance red (Cr) exposure frame, and whereincombining the plurality of frames to provide the image frame comprisesproviding a YCbCr image frame.
 5. The method of claim 1, wherein sensingthe reflected electromagnetic radiation comprises: generating the firstframe based on a pulse of electromagnetic radiation of a first partitionof the electromagnetic spectrum; generating the second frame based on apulse of electromagnetic radiation of a second partition of theelectromagnetic spectrum that is different than the first partition; andgenerating a third frame based on a pulse of electromagnetic radiationof the first partition of the electromagnetic spectrum that is differentthan the first partition and the second partition; wherein the secondframe is captured between the first frame and the third frame; whereindetecting motion across the the plurality of frames comprisescalculating a motion estimate based on the first frame and the thirdframe using block matching; and wherein correcting for the detectedmotion comprises generating a motion compensated frame for the secondframe based on the motion estimate.
 6. The method of claim 5, furthercomprising: determining a first motion vector for the first frame and asecond motion vector for the second frame; and shifting a block ofpixels in the first frame according to the first motion vector.
 7. Themethod of claim 1, further comprising: performing bilinear interpolationon luminance data in the plurality of frames to generate a firstupscaled dataset; performing bicubic interpolation on the luminance datato generate a second upscaled dataset; and calculating a baseline withno interpolation of the luminance data to generate a third upscaleddataset.
 8. The method of claim 7, wherein detecting the motion acrossthe plurality of frames comprises one or more of: segmenting data sensedby the pixel array into segments of pixels and nearest neighboringframes; shifting each segment of pixels in the x direction and comparingwith a neighboring frame at a same resolution to identify motion of anobject being imaged in the x direction; shifting each segment of pixelsin the x direction in sub-pixel increments and comparing to the firstupscaled dataset to identify motion of the object being imaged in the xdirection; shifting each segment of pixels in the y direction andcomparing with a neighboring frame to identify motion of an object beingimaged in the y direction; or shifting each segment of pixels in the ydirection in sub-pixel increments and comparing to the first upscaleddataset to identify motion of the object being imaged in the ydirection.
 9. The method of claim 1, wherein sensing the reflectedelectromagnetic radiation comprises sensing during a readout period ofthe pixel array, wherein the readout period is a duration of time whenactive pixels in the pixel array are read.
 10. The method of claim 1,wherein actuating the emitter comprises actuating the emitter to emit,during a pulse duration, a plurality of sub-pulses of electromagneticradiation having a sub-duration shorter than the pulse duration.
 11. Themethod of claim 1, wherein actuating the emitter comprises actuating theemitter to emit two or more wavelengths simultaneously as a single pulseor a single sub-pulse.
 12. The method of claim 1, wherein the methodfurther comprises providing the fluorescence exposure frame to acorresponding system that determines a location of a tissue structurewithin a scene based on the fluorescence exposure frame.
 13. The methodof claim 12, further comprising: receiving the location of the tissuestructure from the corresponding system; generating an overlay framecomprising the location of the tissue structure; and combining theoverlay frame with the color image frame depicting the scene to indicatethe location of the tissue structure within the scene.
 14. The method ofclaim 13, wherein the tissue structure comprises one or more of a nerve,a ureter, a blood vessel, an artery, a blood flow, or a tumor.
 15. Themethod of claim 1, further comprising synchronizing timing of theplurality of pulses of electromagnetic radiation to be emitted during ablanking period of the image sensor, wherein the blanking periodcorresponds to a time between a readout of a last row of active pixelsin the pixel array and a beginning of a next subsequent readout ofactive pixels in the pixel array.
 16. The method of claim 1, wherein theplurality of frames are captured sequentially in time based on aplurality of pulses of electromagnetic radiation emitted by the emittersequentially in time.
 17. The method of claim 1, wherein sensing thereflected electromagnetic radiation comprises sensing with a first pixelarray and a second pixel array such that a three-dimensional image canbe generated based on the sensed reflected electromagnetic radiation.18. The method of claim 1, wherein actuating the emitter comprisesactuating the emitter to emit a sequence of pulses of electromagneticradiation repeatedly sufficient for generating a video stream comprisinga plurality of color image frames, wherein each color image frame in thevideo stream comprises data from a plurality of frames, and wherein eachof the frames corresponds to a pulse of electromagnetic radiation. 19.The method of claim 1, wherein at least a portion of the plurality ofpulses of electromagnetic radiation emitted by the emitter is anexcitation wavelength for fluorescing a reagent, and wherein at least aportion of the reflected electromagnetic radiation sensed by the pixelarray is a relaxation wavelength of the reagent.
 20. A systemcomprising: an emitter for emitting a plurality of pulses ofelectromagnetic radiation, wherein the emitter comprises a plurality ofelectromagnetic sources; an image sensor comprising a pixel array forsensing reflected electromagnetic radiation to generate a plurality offrames comprising a fluorescence exposure frame resulting from anemission by the emitter of a fluorescence excitation wavelength having awavelength from 770 nm to 795 nm; and one or more processorsconfigurable to execute instructions stored in non-transitory computerreadable storage media, the instructions comprising: identifying aluminance plane in each of a first frame of the plurality of frames anda second frame of the plurality of frames that is subsequent to thefirst frame; detecting motion across the first frame and the secondframe of the plurality of frames based on the luminance planes from eachof the first frame and the second frame; calculating motion in thefluorescence exposure frame based on the detected motion in theluminance planes from each of the first frame and the second frame,wherein the fluorescence exposure frame is generated between the firstframe and the second frame; correcting the fluorescence exposure framebased on the calculated motion; and combining the plurality of frames,after correcting the fluorescence exposure frame for the calculatedmotion, to provide a color image frame with fluorescence image data. 21.The system of claim 20, wherein the instructions are such thatcompensating for the detected motion further comprises: upscaling thefirst frame of the plurality of frames using interpolation to generate afirst upscaled frame; upscaling the first frame without usinginterpolation to generate a second upscaled frame, wherein the secondupscaled frame comprises a first set of empty pixels; filling in thefirst set of empty pixels of the second upscaled frame with pixel datafrom the first upscaled frame; upscaling the second frame of theplurality of frames to generate a third upscaled frame; and filling in asecond set of empty pixels in the second upscaled frame with pixel datafrom the third upscaled frame.
 22. The system of claim 20, wherein theplurality of frames comprises a luminance (Y) frame, a chrominance blue(Cb) frame, and a chrominance red (Cr) frame, and wherein combining theplurality of frames to generate the color image frame comprisesgenerating a YCbCr image frame.
 23. The system of claim 20, wherein theimage sensor is configured to: generate the first frame based on a pulseof electromagnetic radiation of a first partition of the electromagneticspectrum; generate the second frame based on a pulse of electromagneticradiation of a second partition of the electromagnetic spectrum that isdifferent than the first partition; and generate a third frame based ona pulse of electromagnetic radiation of the first partition of theelectromagnetic spectrum that is different than the first partition andthe second partition; wherein the second frame is captured between thefirst frame and the third frame; wherein the instructions are such thatdetecting motion across the plurality of frames comprises calculating amotion estimate based on the first frame and the third frame using blockmatching; and wherein the instructions are such that compensating forthe detected motion comprises generating a motion compensated frame forthe second frame based on the motion estimate.
 24. The system of claim20, wherein at least a portion of the pulses of electromagneticradiation emitted by the emitter results in a fluorescence exposureframe created by the image sensor, and wherein the instructions furthercomprise providing the fluorescence exposure frame to a correspondingsystem that determines a location of a tissue structure within a scenebased on the fluorescence exposure frame.
 25. The system of claim 24,wherein the instructions further comprise: receiving the location of thetissue structure from the corresponding system; generating an overlayframe comprising the location of the tissue structure; and combining theoverlay frame with the color image frame depicting the scene to indicatethe location of the tissue structure within the scene.
 26. The system ofclaim 25, wherein the tissue structure comprises one or more of a nerve,a ureter, a blood vessel, an artery, a blood flow, or a tumor.
 27. Thesystem of claim 20, wherein the image sensor comprises a first imagesensor and a second image sensor such that the image sensor can generatea three-dimensional image.
 28. The system of claim 20, furthercomprising a polarization filter located in a path of the pulses ofelectromagnetic radiation emitted by the emitter.
 29. The system ofclaim 20, further comprising a filter that filters electromagneticradiation having a wavelength from 770 nm to 795-nm.